Keywords

3 World Trade Center/New York Marriott World Trade Center Hotel
A 22-story hotel located in between the Twin Towers. The hotel was destroyed when the Twin Towers collapsed.

4 World Trade Center
A 9-story office building located on the southeast corner of the World Trade Center complex. It was damaged beyond repair when the Twin Towers collapsed.

5 World Trade Center
A 9-story office building located on the northeast corner of the World Trade Center complex. It was damaged beyond repair when the Twin Towers collapsed.

6 World Trade Center/U.S. Custom House
An 8-story office building located on the northwest corner of the World Trade Center complex. It was damaged beyond repair when the Twin Towers collapsed.

7 World Trade Center
A 47-story office building located just north of the World Trade Center complex, across the street from the North Tower. Damaged during the collapse of the Twin Towers, the building collapsed at 5:20 p.m. on 9/11.

9/11 Commission Report
9/11 families advocated for an investigation into weaknesses in the nation’s security and intelligence infrastructure. In response, the U.S. Congress established the bipartisan National Commission on Terrorist Attacks Upon the United States. Known as the 9/11 Commission, the panel of former elected and appointed officials interviewed more than 1,200 individuals, held 19 days of hearings, and heard testimony from government officials, survivors, and terrorism experts. Its July 2004 public report included 41 recommendations on domestic security, intelligence gathering, and foreign policy.

9/11 Perpetrators
Osama bin Laden sought to launch an attack on American soil. Bin Laden’s agenda was shared by Ramzi Yousef, mastermind of the 1993 World Trade Center bombing, and Yousef’s uncle, Khalid Sheikh Mohammed. Only three years apart in age, Khalid Sheikh Mohammed and Ramzi Yousef grew up together in a suburb of Kuwait City. Both were educated in the West—Khalid Sheikh Mohammed in the United States, Ramzi Yousef in the United Kingdom. Together, they plotted an ambitious attack targeting multiple American passenger jets. Although Yousef was already in American custody, by the late 1990s, under Osama bin Laden’s influence, this idea evolved into the 9/11 plot.

al-Qaeda
The terrorist group al-Qaeda was influenced by a strain of 20th-century Islamist thinking that attributed a long decline in the collective power of Muslims to their failure to live in strict accordance with religious law. Founded in 1988 by Saudi-born Osama bin Laden, al-Qaeda has used violence to persuade Muslims worldwide that they could break the influence of the West, and particularly the United States, in Muslim countries. Al-Qaeda cites a number of perceived injustices to legitimize its violence: the oppression of Muslims by regimes supported by the United States, American support for Israel, and the corrupt use of oil-derived wealth. For al-Qaeda, only when Muslims live fully within Islamic law—if necessary, resorting to violence to defeat their opponents—will they be able to reclaim Islam’s destiny of leadership and influence in the world order.

American Airlines Flight 11
On the morning of 9/11, American Airlines Flight 11 took off from Boston. Eleven crew members, 76 passengers, and 5 hijackers were on board. The aircraft was filled with 76,400 pounds of fuel for its transcontinental run to Los Angeles. At 8:46 a.m., Flight 11 crashed into the North Tower of the World Trade Center.

American Airlines Flight 77
On the morning of 9/11, American Airlines Flight 77 took off from Washington Dulles International Airport. Six crew members, 53 passengers, and 5 hijackers were on board. The aircraft was filled with 49,000 pounds of fuel for its transcontinental run to Los Angeles. At 9:37 a.m., Flight 77 crashed into the Pentagon.

Anniversary Observance
Annual commemoration ceremonies and related events.

Arab Americans
Americans of Arab ethnic, cultural, and linguistic heritage or identity who identify themselves as Arab.

Artistic Response
Professional and amateur artists alike have attempted to capture the significance of the 9/11 attacks, honor those lost, and comfort those left behind through various art mediums.

Aviation

Box Beam Columns
Steel columns, known as box columns for their rectangular shape and hollow center, provided structural support for the Twin Towers and created their distinctive facades. Some relatives of 9/11 victims joined with landmark preservationists to advocate that the cutoff columns be designated as historic remnants of the World Trade Center site.

Building Safety
In the wake of the 1993 bombing, the Port Authority’s security team increased emergency preparedness at the World Trade Center. It implemented a fire warden program, staged regular drills, improved stairwell lighting, and coated stairs and handrails with luminescent paint. These changes made it possible for thousands of people in the towers to evacuate safely before the buildings fell on 9/11.

Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF)
The federal law enforcement organization responsible for the investigation and prevention of federal offenses involving the unlawful use, manufacture, and possession of firearms and explosives; acts of arson and bombings; and illegal trafficking of alcohol and tobacco products.

Carpenters

Central Intelligence Agency (CIA)
An independent agency of the United States government responsible for collecting and coordinating intelligence and counterintelligence activities abroad in the national interest.

Children

Children's Art
Children, too, attempted to capture the significance of the 9/11 attacks through artwork. The works created by children in art therapy programs and in school classrooms reflect diverse themes, including violence, patriotism, courage, fear, prejudice, sadness, compassion, and hope.

Collapse
The South Tower collapsed in 10 seconds at 9:59 a.m. on 9/11, after burning for 56 minutes. More than 800 civilians and first responders inside the building and in the surrounding area were killed as a result. The North Tower collapsed at 10:28 a.m., after burning for 102 minutes. More than 1,600 people were killed as a result.

Communications on 9/11
In 2001, the FDNY used analog, point-to-point radios with low signal strength. The radios functioned satisfactorily under most circumstances but historically performed poorly inside steel and concrete high-rise buildings, such as the Twin Towers. On 9/11, radio communications between the lobby command and firefighters on floors above them were sporadic and ineffective. Communications were also complicated because the FDNY and NYPD did not use compatible radios or regularly coordinate command and control functions as part of their standard response procedures. As a result, certain critical information did not reach responders in the towers. Some firefighters and police officers were in face-to-face communication, however, and gained information transmitted over one another’s radios. Telephone service in New York City, whether through landlines or cellular providers, was also sporadic throughout the day. This made it difficult for people to reach family and friends to inform them of their whereabouts.

Conspiracy Theories
A belief that some covert but influential organization or group of people is responsible for a circumstance or event. In the wake of the 9/11 attacks, Americans and people from around the world demanded answers. Government scientists, university researchers, elected officials, counterterrorism experts, and independent analysts studied the causes and consequences of the attacks. Some searched for scientific explanations to facilitate a better understanding of the events and prevent future disasters. Others sought to prove or challenge accounts of what had transpired. Conspiracy theorists have continued to question official narratives.

Counterterrorism
Political or military activities designed to prevent or thwart terrorism. As late as the 1990s, various divisions of the U.S. government had overlapping responsibilities for combating terrorism. Some focused on responding to terrorist threats on American facilities abroad. Others actively sought to prevent an attack on U.S. soil and to train firefighters and police officers in how to respond to a suspected terrorist attack.

Cross at Ground Zero
Volunteer Local 731 construction worker Frank Silecchia found a steel crossbeam in the rubble of 6 World Trade Center on September 13, 2001. The steel, which came to be known as the "Ground Zero Cross," or "Cross at Ground Zero" became a locus for interfaith religious services and a solace to some workers. It was moved to various locations as recovery work continued at the World Trade Center site.

Disaster Mortuary Operational Response Team (DMORT)
A team of experts in the fields of victim identification and mortuary services. DMORT teams assisted the Office of Chief Medical Examiner (OCME) with identifying remains.

Discrimination
The unjust or prejudicial treatment of different categories of people or things, especially on the grounds of race, age, or gender.

Dogs

Electricians

Emergency Medical Services (EMS)
Treatment and transport of people in crisis health situations that may be life threatening.

Engineers

Evacuation
Just before 9:00 a.m., tenants and visitors at the World Trade Center Twin Towers are ordered to commence an evacuation. One minute later the order is expanded to include all civilians in the World Trade Center complex. Later that morning, Mayor Giuliani urged the public to evacuate lower Manhattan.

Faith

Family Member Issues
Many family members turned their grief into action by advocating for a variety of issues such as an independent investigation into the attacks, the rebuilding of the sites, victim compensation, national security, the treatment of human remains, and much more.

Family Members
Relatives of the victims. Within hours of the terrorist attacks, government agencies, American and United Airlines, and the American Red Cross began to establish family assistance centers to serve relatives of the missing and presumed dead. Professional staff and volunteers registered missing person reports and requests for financial assistance, collected DNA samples for victim identification, and helped next of kin obtain expedited death certificates. Pastoral, spiritual, and mental health services were available, as was child care. Translators assisted those not proficient in English. Members of the armed services attended to the needs of Pentagon families, and airline personnel assisted relatives of victims on the flights. The center established near Shanksville, Pennsylvania, served families for several days. The Pentagon’s center was open for a month. The New Jersey Family Assistance Center operated until March 2002. New York City’s center closed in December 2002.

Family Organizations
The selflessness of first responders and many others on and after 9/11, together with the widely experienced impulse to help others in the aftermath of the attacks, forged a connection between 9/11 remembrance and public service. Immediately following the attacks and continuing long after, many channeled their grief and anger by volunteering, enlisting in the military, founding charities, contributing to philanthropic causes, or otherwise helping people in need. Many philanthropic organizations were created by victims' family members and friends as a legacy in memory of their loved ones.

Family Room

Federal Bureau of Investigation (FBI)
A national security and intelligence organization responsible for protecting and defending the United States against terrorist and foreign intelligence threats and for upholding and enforcing the criminal laws of the United States. On 9/11, the FBI deployed agents to each attack site and the airports from which the hijacked flights had departed, setting in motion what became the largest and most complex investigation in its history. Agents worked to identify the hijackers and their accomplices and to deter future attacks.

Federal Emergency Management Agency (FEMA)
An agency of the U.S. Department of Homeland Security created to coordinate the response to a disaster that overwhelms the resources of local and state authorities. On 9/11, FEMA Urban Search and Rescue teams from 14 states supported the work of local police and firefighters at Ground Zero.

First Responders
Individuals or agencies designated or trained to respond to an emergency. Approximately 2,000 police officers and nearly 1,000 firefighters deployed in response to the attacks on the World Trade Center. More than 100 city and volunteer ambulances were dispatched to the scene within the first hour. In all, they formed the largest emergency mobilization in New York City history. At the Pentagon, emergency response agencies from the National Capital Region formed a unified command. The Arlington County Fire Department assumed command of the scene and directed fire suppression and rescue operations. Units trained and equipped to fight jet fuel fires came from nearby Ronald Reagan Washington National Airport. The Pentagon’s Defense Protective Service aided in the evacuation and worked with the FBI to secure the crime scene.

Fresh Kills Landfill
The Fresh Kills facility on Staten Island, a former landfill slated to become park land, reopened on September 12, 2001 to provide an area for investigators to analyze and further search the wreckage of the World Trade Center. During the recovery period, more than one million tons of World Trade Center material were transported by truck and barge to the Fresh Kills Landfill for sorting.

Funerals
Public memorial ceremonies and private funerals began to be held for 9/11 victims within a week of the attacks. The scale and nature of the destruction made it difficult and, in the case of the World Trade Center and Pentagon, impossible to recover and identify all who were killed there. Some families acknowledged their losses with memorial services, even when they had received no remains. Over time, as fragmented remains were found and identified at Ground Zero, some victims’ families faced the need for multiple funerals. Memorial services and funerals continued for years.

Ground Zero
Within hours of the attacks, some rescue workers and journalists begin referring to the scene of mass destruction at the World Trade Center site as Ground Zero, a term typically used to describe devastation caused by an atomic bomb. During the nine-month recovery and cleanup operation at the World Trade Center, many thousands of individuals transformed what some called "the pile"—a scene of mass destruction dominated by a vast mountain of tangled steel—into an excavated pit reaching 70 feet below ground.

Health Effects
The 9/11 attacks have continued to affect the health and well-being of victims’ families and friends, survivors, rescue and recovery workers, cleaning crews, and those living and working in the vicinity of the three crash sites. Some injuries were immediately obvious, requiring hospitalization, surgeries, and lengthy recuperations. Other injuries were less apparent, including emotional scars and later illnesses. Questions arose about the long-term impact of exposure to the dust clouds that formed when the towers collapsed on 9/11 and the dangers of working at the site during the recovery. Days after the attack, the U.S Environmental Protection Agency declared the air in lower Manhattan safe. Subsequent tests showed that omnipresent dust—made of pulverized building materials, industrial chemicals, and electronics mingled with jet fuel residue—was hazardous.

Heavy Equipment Operators

Heroism

Hijackers
Leaders of al-Qaeda selected the 19 hijackers who carried out the 9/11 attacks from a pool of young men who attended terrorist training camps in Afghanistan. The leaders ultimately chose as pilots four individuals who, having lived in the United States and Western Europe, would be unobtrusive while attending a U.S. flight school. Al-Qaeda leaders trained additional recruits as “muscle hijackers” and taught them how to take over a plane by physically subduing passengers and crew. Al-Qaeda leaders characterized selection for a suicide attack as an honor.

Hospitals
Institutions providing medical and surgical treatment and nursing care for sick or injured people. Expecting thousands of injured survivors from the World Trade Center, hospitals prepared for care that was not needed due to mass fatalities.

Human Remains
The New York City Office of Chief Medical Examiner launched the most complex forensic investigation in U.S. history, bringing together DNA experts, dentists, anthropologists, and other forensic specialists to maximize the number of positive identifications. Their efforts significantly advanced the technology used to extract usable DNA from minuscule samples, more than doubling the total number of victims identified. Remains for all Flight 93 victims were recovered, but remains for five Pentagon victims were never identified. A decade after the attacks, remains of approximately 40 percent of World Trade Center victims had not been identified. The commitment to use increasingly precise DNA analysis to identify World Trade Center victims is ongoing. Even with such advances, a large number of remains may elude positive identification.

Incident Management
Refers to command structures and coordination among different agencies during the initial incident and subsequent recovery period.

International Response
The death toll on 9/11 included individuals from more than 90 nations and stirred sympathy around the globe. While the response was not universally supportive, most world leaders, including heads of state in countries not allied with the United States, offered statements of condolence to the American people and condemned the acts of terrorism.

Ironworkers

Islam
Islam is one of the world’s major religions. Adherents of Islam are known as Muslims. Islamism is a political movement asserting that Muslims should be governed strictly according to Islamic law, known as sharia. Islamists seek political and religious control of Muslim countries. There are differing perspectives among Islamists about when and if violence can be used to achieve their aims.

Jihad
"Struggle in defense of Islam." A war against unbelievers.

Koenig’s Sphere
Installed between the Twin Towers in 1971, Fritz Koenig's sculpture sat atop a fountain that flowed across a circular expanse of polished stone; the sculpture was designed to slowly rotate. The Sphere was at the heart of the World Trade Center’s five-acre public Plaza. Regarded as a symbol of world peace, The Sphere sustained significant damage in the terrorist attack on 9/11 and emerged as a lasting symbol of resilience. In March 2002, it was installed in Battery Park as a temporary memorial to the victims of 9/11.

Laborers

Lady Liberty
Soon after 9/11, a Statue of Liberty replica appeared on the sidewalk in front of a Manhattan firehouse. Home to FDNY Engine Company 54, Ladder Company 4, and Battalion 9, the firehouse lost 15 firefighters at the World Trade Center on 9/11. People walking past the building began to place small American flags, condolence messages, prayer cards, rosary beads, patches bearing military and uniformed service insignia, money, and other tribute items on the statue, which soon became known as Lady Liberty.

Last Column
As the work of clearing the World Trade Center site neared completion, one piece of steel was chosen to mark the occasion symbolically. Designated the Last Column, it was removed from the site in a solemn ceremony held on May 30, 2002. In the weeks that preceded its departure, recovery workers, first responders, volunteers, and victims’ relatives signed the column and affixed to it memorial messages, photographs, and other tributes.

Lower Manhattan Residents
Approximately 37,000 households were located south of Canal Street in 2001. After 9/11, residents had to show proof of residence to enter and were allowed only brief access to retrieve possessions from their homes, many of which were damaged by dust and debris from the collapsed towers. While some lower Manhattan residents returned within days, most were displaced for weeks, and others for more than a year.

Media
Approximately two billion people, almost one third of the world’s population, are estimated to have witnessed the events of 9/11 directly or via television, radio, and Internet broadcasts that day. By late morning on September 11, 2001, the attack on America had become the lead—and in some cases, the only—news story around the world. In the United States, coverage of the disaster and the emergency response replaced regular programming on almost all television channels. Coverage was uninterrupted by commercial advertising throughout the day and evening.

Medical Professionals
Medical personnel arrived at the World Trade Center site throughout the day, anticipating that lifesaving measures would be needed. However, as hours passed and few survivors were rescued, they turned to treating first responders who were having trouble breathing and rinsing eyes that were irritated by smoke and grit.

Memorialization
By late afternoon on September 11, 2001, the urge to mourn alongside others brought people together throughout New York City and across the country. In the days that followed, people gathered on college campuses, in parks and town halls, in places of worship, and elsewhere. Across the nation, flags were flown at half staff in recognition of the country’s loss. Spontaneous memorials appeared in town squares, on roadside billboards, in murals painted on the sides of buildings, and outside firehouses and police stations. Permanent memorials grew over time.

Middle East Politics

Missing Posters
In the days following 9/11, relatives and friends of those who had not returned home from the World Trade Center posted missing person fliers at hospitals, family assistance centers, and public places throughout the city. Hoping their loved ones were still alive, relatives showed missing posters to anyone likely to have seen the people in question, as well as to television reporters who could broadcast the images more widely. As the chances for survival faded, the posters themselves became memorials, adorned with messages, flowers, flags, and personal tributes.

National Security

New York City Department of Corrections
The city agency responsible for the care, custody, and control of persons accused of crimes or convicted and sentenced to one year or less of jail time.

New York City Department of Design & Construction (DDC)
The city agency responsible for capital construction. After 9/11, the DDC provided engineering and construction support to the FDNY in the early recovery period and later oversaw the entire recovery operation at the site. Confronted with approximately 1.8 million tons of debris, the DDC split the site into four zones and assigned four construction companies—AMEC, Bovis Lend Lease, Tully Construction, and Turner Construction—oversight of particular quadrants.

New York City Department of Sanitation (DSNY)
The city agency responsible for waste management. After 9/11, the DSNY worked to clear the streets around the perimeter of Ground Zero. Personnel removed crushed cars, debris, and other large obstacles to allow passage of emergency crews and construction equipment heading to the site. DSNY also assisted with the forensic operation at Fresh Kills Landfill on Staten Island.

New York City Fire Department (FDNY)
The city agency responsible for fire protection and other critical public safety services to residents and visitors in the five boroughs of New York City. Nearly 1,000 firefighters deployed in response to the attacks on the World Trade Center; 343 members of the FDNY died on 9/11.

New York City Office of Chief Medical Examiner (OCME)
The city agency responsible for investigating cause of death. The agency was tasked with identifying remains of those who perished at the World Trade Center, a process that expanded into the largest forensic DNA investigation in U.S. history. On 9/11, the OCME immediately established temporary field mortuaries in buildings around the perimeter of the World Trade Center site to assist with the recovery of remains. Its operations expanded to Bellevue Hospital which served as headquarters for the identification of remains. The OCME continues to preserve all unidentified remains in the hope that future technological breakthroughs may make additional identifications possible.

New York City Office of Emergency Management (OEM)
In 2001, the Mayor’s Office of Emergency Management was a newly formed agency comprised of personnel drawn from the police, fire, and other emergency agencies. Headquartered on the 23rd floor of 7 World Trade Center, the agency operated a citywide command center equipped with the most up-to-date communications technology. Its interagency mandate and equipment enabled direct communication with FDNY and NYPD commands.

New York City Office of the Mayor
As soon as New York City Mayor Rudolph Giuliani learned that a plane had hit the World Trade Center, he rushed to the site for a briefing with emergency officials, to be followed by a press conference. After the South Tower collapsed, the Mayor and senior members of his administration found temporary shelter inside an office building close by. As the dust began to settle, they walked north, intent on establishing a new base of operations for city government.

New York City Police Department (NYPD)
The city agency responsible for enforcing the law, preserving peace, and maintaining order for all residents and visitors in the five boroughs of New York City. More than 2,000 police officers from the NYPD and PAPD responded to the World Trade Center throughout the day on 9/11. Some, particularly in the Emergency Service Units, entered the Twin Towers prepared to rescue trapped civilians. Many directed thousands of survivors to exit safely and guided injured evacuees to medical assistance. Police officers stationed in the lobbies, the Plaza, or on the streets surrounding the World Trade Center provided support and direction to those confronting falling debris. They also kept bystanders out of harm’s way. Twenty-three members of the NYPD died on 9/11.

New York City Police Department Emergency Service Unit (ESU)
Members of the NYPD’s Emergency Service Unit (ESU) are trained in search and rescue, weaponry, and hazardous materials containment. All 10 ESU squads responded to the World Trade Center. Fourteen ESU officers were killed on 9/11.

North Tower
The North Tower rose 1,368 feet, 1,730 feet including a large antenna. On a clear day, views extended 45 miles from the top of the towers in every direction, far enough to see all five New York City boroughs, New Jersey, and Connecticut. On 9/11, the North Tower was hit by American Airlines Flight 11 at 8:46 a.m. At 10:28 a.m., it was the second tower to collapse.

Paramedics
Medical personnel, including paramedics trained in emergency first aid, arrived at the World Trade Center site, anticipating that lifesaving measures would be needed.

Patriotism
The 9/11 attacks stirred patriotic feelings. Some individuals were inspired to enlist in the U.S. military. Others hung flags at home and work. Consumer demand for American flags in the wake of 9/11 was so high that factories and stores in the U.S. and abroad struggled to keep pace. By the end of September, one factory in China had received orders for more than 500,000 flags.

Pentagon
At 9:37 a.m. on the morning of September 11, American Airlines Flight 77 crashed into the Pentagon. The crash and ensuing fire killed all on board the plane and 125 military and civilian personnel on the ground.

Pet Rescue
Efforts made to rescue pets left in lower Manhattan following the evacuation of the area.

Philanthropic Response
The selflessness of first responders and many others on and after 9/11, together with the widely experienced impulse to help others in the aftermath of the attacks, forged a connection between 9/11 remembrance and public service. Immediately following the attacks and continuing long after, many people channeled their grief and anger by volunteering (with organizations such as the American Red Cross and the Salvation Army), enlisting in the military, founding charities, contributing to philanthropic causes, or otherwise helping people in need.

Photographer and Videographer: Amateur
As events unfolding at the World Trade Center escalated, thousands of people, amateurs and professionals, photographed and filmed the scene. 9/11 remains one the most widely documented breaking news events of its time.

Photographer and Videographer: Professional
As events unfolding at the World Trade Center escalated, thousands of people, amateurs and professionals, photographed and filmed the scene. 9/11 remains one the most widely documented breaking news events of its time.

Point Thank You
Supporters carrying signs and banners gathered along the West Side Highway, on Manhattan's west side, to cheer for the recovery and relief workers traveling to and from Ground Zero. Many supporters converged at the intersection of Christopher Street and West Street, in Greenwich Village. This location became known as "Point Thank You."

Port Authority of New York and New Jersey (PANYNJ)
The interstate agency that created and managed the World Trade Center until July 24, 2001. The Port Authority maintained offices in both the North and South Towers on 9/11. Thirty-four employees were killed on 9/11.

Port Authority Police Department (PAPD)
The World Trade Center was protected by the Port Authority Police Department (PAPD). This police force is responsible for the safety and security of the port of New York and New Jersey, bridges and tunnels spanning the Hudson River, and airports in the metropolitan area. At the World Trade Center, PAPD police desks were located in 5 World Trade Center and in the underground concourse. PAPD officers throughout the complex mobilized on 9/11. Members of the department at posts elsewhere in the city and in New Jersey arrived on the scene soon thereafter. Thirty-seven members of the PAPD were killed on 9/11.

Post-9/11 World
The legacy of the 9/11 attacks continues to define policy debates, civic discourse, and reflections on public safety, global politics, civil liberties, and finding the right balance between remembering and rebuilding.

Public Reaction
By late afternoon on September 11, 2001, the urge to mourn alongside others brought people together throughout New York City and across the country. In the days that followed, people gathered on college campuses, in parks and town halls, in places of worship, and elsewhere. Across the nation, flags were flown at half staff in recognition of the country’s loss. Most of the world offered condolences to the people and government of the United States. There were, however, some spontaneous public celebrations of the 9/11 attacks, expressions of support for violent Islamism, and organized demonstrations of opposition to American foreign policy.

Radio Row
Construction of the World Trade Center in the late 1960s created an urban superblock over what had previously been a maze of commercial and residential streets. Among the neighborhoods eliminated was the stretch of Greenwich Street between Dey Street, to the north, and Liberty Street, to the south, commonly referred to as Radio Row. Known for its numerous mom-and-pop electronic shops, Radio Row was home to more than 350 small businesses in 1966.

Rebuilding After 9/11
Established in October 2001, the Lower Manhattan Development Corporation (LMDC) received $2.8 billion in federal funding to support plans for revitalizing downtown, including rebuilding the World Trade Center site. The LMDC held hundreds of public hearings and consulted with the 9/11 community as plans for the site developed. On September 15, 2001, the U.S. Department of Defense announced that it had awarded a contract for immediate reconstruction of the Pentagon’s damaged areas. The crew met its ambitious goal of rebuilding 400,000 square feet of office space by September 11, 2002.

Recovered Property
Tens of thousands of pieces of personal property were found and inventoried by the NYPD Property Clerk Division, charged with returning recovered items to World Trade Center occupants and victims’ relatives. The NYPD provided a private area for families to receive their loved ones’ belongings. Objects recovered from Ground Zero came from the highest and lowest areas of the buildings, from the top floors of the towers to their subterranean basement levels. Recovered property was also found at the Pentagon and at the Flight 93 crash site.

Rescue and Recovery
Within hours of the 9/11 attacks, millions of people across the world felt compelled to respond to the crisis. Volunteers and trained professionals rushed to help in the rescue and recovery efforts at the World Trade Center, Pentagon, and Flight 93 sites. Months were spent extinguishing fires, searching for survivors, and, ultimately, searching for remains of the victims. It took nine months to remove approximately 1.8 million tons from the World Trade Center site.

Respite/Relief Center
The American Red Cross and Salvation Army operated mobile relief stations following 9/11, and opened indoor respite and relief centers shortly after the attacks. Staffed largely by volunteers, these centers offered a range of services, including meals, medical care, rest areas, and mental health support. Some were kept open 24 hours a day, seven days a week.

Rumors
Circulating stories or reports of uncertain accuracy. As the events of 9/11 unfolded, many people speculated about the cause, who or what was responsible, and what would happen next.

Schools

Security
After the 1993 bombing, the Port Authority took action to strengthen security at the World Trade Center. At a cost of $50 million, security improvements transformed it from an open complex into one with access restricted to those conducting business within its confines. The parking garage was closed to the public, but the outdoor Plaza and belowground shopping mall remained public amenities. Entrance to the buildings was regulated through encoded photo identification cards issued to tenants and registered guests. These changes made it increasingly difficult for unauthorized persons or vehicles to gain access to the complex. At that time, this level of security screening was unusual.

September 11th Victim Compensation Fund (VCF)
Established by Congress in September 2001, the September 11th Victim Compensation Fund was established “to provide compensation to any individual (or relatives of a deceased individual) who was physically injured or killed as a result of [the September 11th attacks].” Ninety-seven percent of eligible victims’ families submitted claims to the fund. In total, the fund issued 5,560 awards totaling more than $7 billion.

Shanksville (Somerset County, Pennsylvania)
United Airlines Flight 93 crashed in a field near the town of Shanksville in Somerset County, Pennsylvania on 9/11. The crash site is approximately 20 minutes’ flying time from Washington, D.C.

Slurry Wall
The proximity of the Hudson River presented a significant challenge to the planners of the World Trade Center. Before excavation and construction could begin in 1966, it was necessary to find a way to prevent river water from seeping into or flooding the site. The innovative solution was to build a concrete retaining wall, known as a slurry wall. Despite fears that it might be breached on 9/11, thereby worsening the catastrophic impact of the attacks, the wall held.

South Tower
The South Tower stood 1,362 feet high. On a clear day, views extended 45 miles from the top of the towers in every direction, far enough to see all five New York City boroughs, New Jersey, and Connecticut. On 9/11, the South Tower was hit by United Airlines Flight 175 at 9:03 a.m. At 9:59 a.m. it was the first tower to collapse.

South Tower Observation Deck
At 1,377 feet, the South Tower Observation Deck’s outdoor viewing platform was the highest in the world. On a clear day, one could see for 45 miles in each direction from the Observation Deck. On average, the Observation Deck attracted 1.8 million visitors per year. From the opening day of the Observation Deck in December 1975, through close of business the night of September 10, 2001, approximately 46,350,000 visitors experienced the views from the top of the South Tower.

Soviet Afghan War (1979-1989)
The Soviet Union invaded Afghanistan in late December 1979. The Soviets aimed to protect the Afghan communist government, threatened by an armed uprising of Afghans of diverse political and ethnic backgrounds. These fighters were called mujahideen, a term for warriors engaged in waging a jihad to defend Islam. Ultimately, nearly a decade of war claimed the lives of approximately a million Afghans and almost 15,000 Soviets. Having failed to defeat the Afghan rebels, the Soviet superpower completed its withdrawal from Afghanistan in 1989.

Survivor Tree

Survivors
Persons who survive, especially persons remaining alive after an event in which others have died.

Taliban
Civil war broke out in Afghanistan after the Soviet Union withdrew its troops in 1989. Rival militias, often organized along tribal or ethnic lines, controlled different parts of the country. In 1994, the Taliban—“students” in the Pashto language—coalesced in southern Afghanistan to oppose the brutal and corrupt rule of local warlords. Fighting to impose Islamic law, the Taliban brought stability and gained popularity among fellow Pashtuns, the dominant ethnic group in southern Afghanistan. As the fight intensified, the Taliban was fortified by thousands of young Afghan Pashtuns from religious seminaries based in Pakistan. The Taliban took control of Afghanistan’s capital, Kabul, in 1996 and imposed its harsh version of Islamic law, seeking to control all aspects of social life and severely limiting the rights of women. Taliban leaders were sympathetic to al-Qaeda’s anti-American message and permitted Osama bin Laden to operate within Afghanistan. In exchange, bin Laden provided the Taliban with money and men to fight in the continuing Afghan civil war.

Teamsters

Terrorism
The use of violence and intimidation in the pursuit of political aims.

The Hunt for Osama bin Laden
In a televised speech from the White House on May 1, 2011, U.S. President Barack Obama delivered the news that Osama bin Laden, the al-Qaeda leader responsible for the 9/11 attacks, had been killed in a targeted military strike carried out by U.S. Navy SEALs.

Tolerance
The ability or willingness to accept something, in particular the existence of opinions or behavior that one does not necessarily agree with.

Tribute in Light
Tribute in Light is a commemorative public art installation first presented six months after 9/11 and then every year thereafter, from dusk to dawn, on the night of September 11. Visible as far as 60 miles from lower Manhattan and reaching up to four miles into the sky, the twin beams were conceived by several artists and designers. Tribute in Light was designed to evoke the memory of the Twin Towers and the brightness of too many lives taken far too soon.

Tributes
Flowers, candles, flags, and other commemorative items left at or near locations of the attacks or other areas where people gathered to memorialize the events.

Twin Towers
The Twin Towers were the centerpieces of the World Trade Center complex. At 110 stories each, 1 WTC (North Tower) and 2 WTC (South Tower) provided nearly 10-million-square feet of office space. They were the tallest buildings in New York City, and for a brief period upon their completion, they were the tallest buildings in the world. They attracted tens of thousands of commuters and tourists every day.

United Airlines Flight 175
On the morning of September 11, 2001, United Airlines Flight 175 took off from Boston. Nine crew members, 51 passengers, and 5 hijackers were on board. The aircraft was filled with 76,000 pounds of fuel for its transcontinental run to Los Angeles. At 9:03 a.m., Flight 175 crashes into the South Tower of the World Trade Center.

United Airlines Flight 93
On the morning of September 11, 2001, United Airlines Flight 93 took off from Newark International Airport. Seven crew members, 33 passengers, and 4 hijackers were on board. The aircraft was filled with 48,700 pounds of fuel for its transcontinental run to San Francisco. At 10:03 a.m., Flight 93 crashed into a field near the town of Shanksville in Somerset County, Pennsylvania.

United States Military
On September 27, 2001, President Bush authorized the use of the U.S. National Guard to increase security at airports. By year’s end, more than 50,000 members of the National Guard would be mobilized to support homeland defense and the war in Afghanistan.

Vesey Street Stair Remnant
The Vesey Street stair remnant or, the"Survivors' Stairs," once connected the northern edge of the World Trade Center’s Austin J. Tobin Plaza to the Vesey Street sidewalk below. On September 11, 2001, the stairs and an adjacent escalator provided an unobstructed exit for hundreds seeking to escape. To reach the stairs, many had to cross the Plaza beneath treacherous debris falling from the North Tower.

Victim Personal Property
Personal effects belonging to those killed in the attacks. These items were contributed by family members, friends, and colleagues to represent the lives of their loved ones. Distinguished from recovered property.

Victim Personal Property: Athletics, Hobbies, and Skills
Many family members, friends, and colleagues have contributed personal effects belonging to their loved ones that represent specific interests in hobbies, sports, or special skills. Distinguished from recovered property.

Victims
2,977 individuals were killed as a result of the terrorist acts of September 11, 2001, at the World Trade Center as well as at the Pentagon and in Somerset County, Pennsylvania. Six individuals were killed in the terrorist bombing of the World Trade Center on February 26, 1993.

Volunteers
Volunteers of every age, background, and ability flocked to Ground Zero, intent on supporting the rescue and recovery. Some signed on with organizations such as the American Red Cross and the Salvation Army, while others volunteered independently.

War on Terrorism
To prevent future attacks after 9/11, the U.S. government initiated a Global War on Terror, sending troops to Afghanistan and later to Iraq. One of the objectives was to undermine terrorism by enabling open, democratic elections in countries governed by repressive regimes. Many Americans joined the military to defeat supporters of terrorism.

Windows on the World
A complex of venues at the top floors (106th and 107th) of the North Tower of the World Trade Center that included a restaurant called Windows on the World, a smaller restaurant called Wild Blue, a bar called The Greatest Bar on Earth, and rooms for private functions.

Witnesses
Thousands of people directly witnessed the attacks on the World Trade Center and the Pentagon. Whether running from danger or at a distance, many on the streets felt compelled to stop, unable to avert their eyes from the unfolding scenes of horror. Approximately two billion people, almost one third of the world’s population, are estimated to have witnessed the events of 9/11 directly or via television, radio, and Internet broadcasts that day.

World Trade Center Building Complex
The World Trade Center consisted of 7 buildings, spanning 16 acres. The complex housed office space, an observation deck, the "Windows on the World" restaurant, and an underground shopping mall. It served as a transit hub for New Jersey PATH train and New York City subway riders. About 50,000 people worked at the WTC complex, with another 40,000 passing through daily.

World Trade Center Plaza
Architect Minoru Yamasaki included a five-acre traffic-free Plaza in his design for the World Trade Center. Its amenities ranged over time from sculpture commissioned for the site to benches and planters filled with seasonal plants. Musical and theatrical performances were held during warm weather. In 1982, the Plaza was named in memory of Austin J. Tobin, the Port Authority executive director who oversaw construction of the complex.

World Trade Center: 1993 Bombing
On February 26, 1993, Islamist terrorists drove a van loaded with approximately 1,200 pounds of explosives into the public parking garage beneath the World Trade Center. They escaped in a waiting car before the bomb exploded at 12:18 p.m. The blast killed six adults, including a pregnant woman. More than a thousand building occupants and emergency responders were injured, but the terrorists’ mission to topple the buildings failed.

World Trade Center: Concourse Level
The belowground concourse level of the World Trade Center housed a large, busy indoor shopping mall. Many shops opened early in the morning to accommodate office workers and commuters using the subway and PATH train stations. Tourists and neighborhood residents also used the mall to purchase anything from a newspaper to luxury goods, fill a prescription, enjoy a meal, get a key copied, or make a financial transaction.

World Trade Center: Dust
Made of pulverized building materials, industrial chemicals, and electronics mingled with jet fuel residue, the dust created from the collapse of the Twin Tower contained asbestos, lead, mercury, benzene, silica, and man-made vitreous fibers.

World Trade Center: Original Construction
When the Twin Towers opened in 1973, they were the tallest buildings on earth, reaching over a quarter mile into the sky. With one acre per floor and a total of nearly 10 million square feet of rentable space, the towers were also the world’s largest office buildings. It took 13 years to plan and complete the World Trade Center, including 7 years of construction. Its developers faced challenges specific to local geology and high-rise construction. The novel engineering and architectural solutions they devised revolutionized skyscraper construction.

World Trade Center: Steel
The Twin Towers were built using modular construction methods designed to save time and money. Ironworkers assembled the towers from 200,000 tons of prefabricated structural steel supplied by eight manufacturers based across the United States. Each piece of steel was stamped with a code indicating its ultimate placement.

World Trade Center: Visitor and Worker Experiences
As of 2001, the World Trade Center was home to more than 430 businesses from 28 different countries. Approximately 50,000 people worked in the World Trade Center with tens of thousands more passing through the complex each day. The World Trade Center complex contained 12 million square feet of office space and 22 different food and drink vendors.

Worn or Used After 9/11
Clothing, uniforms, or equipment worn or used at Ground Zero, the Pentagon, or the Flight 93 crash site during the respective recovery periods.

Worn or Used on 9/11
Clothing, uniforms, or equipment worn or used on September 11, 2001.

Zadroga Act
The James Zadroga 9/11 Health and Compensation Act was passed by Congress in 2010. The landmark bill provides financial compensation to individuals who suffered physical injury or death as a result of the 9/11 attacks and establishes a program to monitor and treat those with 9/11-related health conditions. As of February 2014, more than 50 types of cancers had been included on the official list of conditions covered by the $4.3 billion bill. The bill is named after a New York City homicide detective, James Zadroga, who died in 2006 at the age of 34 and who had worked at Ground Zero for roughly 3 weeks.