September 11 Attacks (2001): The Day That Changed the World

The September 11 attacks were a series of coordinated suicide attacks carried out by the militant Islamist network al-Qaeda against the United States on the morning of Tuesday, 11 September 2001. Nineteen hijackers seized four passenger airliners, crashing two into the World Trade Center in New York City and one into the Pentagon near Washington, D.C., while the fourth came down in a field in Pennsylvania. With 2,977 victims, it remains the deadliest terrorist attack in history, and it reshaped American foreign policy, global security and international politics for a generation.

Background: al-Qaeda and its war on the United States

Al-Qaeda (“the base”) emerged in the late 1980s from the networks of Arab volunteers who had fought against the Soviet occupation of Afghanistan. Its leader, Osama bin Laden, was the son of a wealthy Saudi construction family. After the 1990–1991 Gulf War he turned against the Saudi monarchy and the United States, objecting above all to the stationing of American troops in Saudi Arabia, and also to US support for Israel and sanctions on Iraq.

From 1996 bin Laden was based in Afghanistan under the protection of the Taliban regime. In 1996 and again in February 1998 he issued declarations calling on Muslims to kill Americans. Al-Qaeda then carried out the bombings of the US embassies in Kenya and Tanzania in August 1998, which killed 224 people, and the suicide attack on the destroyer USS Cole in Yemen in October 2000, which killed 17 American sailors.

The idea of using hijacked aircraft as missiles came from Khalid Sheikh Mohammed, a militant of Pakistani Baluch origin raised in Kuwait, whose nephew, Ramzi Yousef, had organised the first bombing of the World Trade Center in 1993. Bin Laden approved the “planes operation” around 1999. Its core pilots came from a group of students in Hamburg, Germany, led by the Egyptian Mohamed Atta, who moved to the United States in 2000 and took flying lessons there. Fifteen of the 19 hijackers were Saudi citizens; two came from the United Arab Emirates, one from Egypt and one from Lebanon.

What happened on 11 September

The hijackers boarded four transcontinental flights, chosen because they carried large loads of fuel. Each team included a trained pilot. Armed with knives and box cutters, and in some cases claiming to have bombs, they took control of the aircraft shortly after take-off.

At 8:46 a.m. Eastern time American Airlines Flight 11, flying from Boston to Los Angeles and piloted by Atta, struck the North Tower of the World Trade Center. Many people at first assumed it was an accident. At 9:03 a.m., with television cameras trained on the burning tower, United Airlines Flight 175, also from Boston, hit the South Tower. It was now clear that the United States was under attack.

At 9:37 a.m. American Airlines Flight 77, which had left Washington Dulles International Airport for Los Angeles, crashed into the western side of the Pentagon in Arlington, Virginia, the headquarters of the US Department of Defense. The Federal Aviation Administration ordered all civilian aircraft over the United States to land, the first such nationwide grounding in its history, and some 4,500 planes were brought down within hours.

United Airlines Flight 93, flying from Newark to San Francisco, had taken off late and was hijacked at about 9:28 a.m. Using seat-back and mobile phones, passengers and crew learned of the attacks in New York and Washington. At 9:57 a.m. they began an assault on the cockpit. The hijacker pilot, Ziad Jarrah, rolled and pitched the aircraft, and at 10:03 a.m. it crashed into a field near Shanksville, Pennsylvania, about 20 minutes’ flying time from Washington. Investigators concluded that its target was probably the US Capitol or the White House.

The collapse of the towers

In New York, thousands of people evacuated the towers down smoke-filled stairwells, while firefighters, police officers and paramedics climbed up to rescue them. Above the impact zones, however, the stairways were blocked or impassable in the North Tower, and nearly everyone trapped there died.

At 9:59 a.m. the South Tower collapsed, 56 minutes after it had been hit. The North Tower fell at 10:28 a.m., after burning for 102 minutes. The collapses killed many of those still inside and hundreds of rescuers in the lobbies and streets below, and buried Lower Manhattan in a cloud of pulverised concrete, glass and asbestos. Late that afternoon, at 5:21 p.m., the 47-storey 7 World Trade Center, damaged by debris and burning without water to fight the fires, also collapsed. Nobody died in that collapse because it had been evacuated.

Key people

Osama bin Laden led al-Qaeda and approved the plot. He at first denied involvement but in a video released in 2004 openly claimed responsibility. He was killed by US special forces in Abbottabad, Pakistan, in May 2011 (see the killing of Osama bin Laden).

Khalid Sheikh Mohammed, described by the 9/11 Commission as the principal architect of the attacks, was captured in Pakistan in 2003 and held at Guantánamo Bay. His military commission trial has been delayed for many years by legal disputes, including over his treatment in CIA custody.

Mohamed Atta was the operational leader of the hijackers and flew Flight 11. George W. Bush, President since January 2001, was visiting a primary school in Sarasota, Florida, when he was told of the attacks; he addressed the nation from the White House that evening. Rudy Giuliani, Mayor of New York, became a prominent public figure in the days after the attacks.

The human cost

The attacks killed 2,977 people from more than 90 countries, not counting the hijackers. In New York about 2,750 died, including passengers and crew of the two aircraft. Among them were 343 firefighters of the New York City Fire Department, 23 New York City police officers and 37 officers of the Port Authority Police Department, making it the deadliest day for American firefighters and police in history. At the Pentagon 184 people were killed, 125 in the building and 59 aboard Flight 77, and 40 passengers and crew died on Flight 93.

The toll did not end in 2001. Rescue and recovery workers and residents breathed the toxic dust of “Ground Zero” for months. Tens of thousands of people have since been treated for cancers and respiratory diseases linked to the site, and many responders have died of these illnesses. The James Zadroga 9/11 Health and Compensation Act of 2010 created a federal programme to monitor and treat them.

Response and investigations

On 12 September 2001 NATO invoked Article 5 of its founding treaty, which states that an attack on one member is an attack on all, for the first time in its history. On 14 September Congress passed the Authorization for Use of Military Force, which President Bush signed four days later, allowing force against those responsible and those who harboured them.

When the Taliban refused to hand over bin Laden, the United States and Britain began air strikes on Afghanistan on 7 October 2001, opening the War in Afghanistan. The Taliban regime fell within weeks, but bin Laden escaped, probably from the Tora Bora mountains into Pakistan, in December 2001.

At home, the USA PATRIOT Act of 26 October 2001 widened the government’s powers of surveillance and investigation. The Transportation Security Administration was created in November 2001, and the Homeland Security Act of 2002 created the Department of Homeland Security, the largest reorganisation of the US government since the Second World War. The New York Stock Exchange stayed closed until 17 September, its longest closure since 1933.

Investigations

The National Commission on Terrorist Attacks Upon the United States, known as the 9/11 Commission and chaired by the former New Jersey governor Thomas Kean, published its report in July 2004. It found that US agencies had missed several opportunities to disrupt the plot, partly because the CIA and FBI failed to share information, and described a “failure of imagination” in anticipating this kind of attack. Its recommendations led to the creation of the post of Director of National Intelligence in 2004.

The commission also found no evidence of a collaborative operational relationship between al-Qaeda and Saddam Hussein’s Iraq. Nevertheless, the attacks formed part of the backdrop to the American-led Iraq War of 2003.

Myths and facts

The attacks gave rise to a number of conspiracy theories, most prominently the claim that the towers and 7 World Trade Center were brought down by planted explosives. Detailed investigations by the National Institute of Standards and Technology (NIST), published in 2005 and 2008, concluded that the towers collapsed because of aircraft damage and fire, and that 7 World Trade Center was the first known tall building to collapse primarily because of uncontrolled fire. These findings are accepted by the great majority of engineers.

It is also sometimes said that the hijackers were mainly Afghans or Iraqis. In fact none were; most were Saudi citizens, and the training camps used by al-Qaeda were in Afghanistan.

Legacy

Ground Zero was cleared of an estimated 1.8 million tons of debris by May 2002. The National September 11 Memorial, with two pools set in the footprints of the Twin Towers, opened on the tenth anniversary in 2011, and its museum in 2014. One World Trade Center, rising to a symbolic 1,776 feet (541 metres), opened in November 2014. Memorials also stand at the Pentagon and at the Flight 93 National Memorial near Shanksville.

The “War on Terror” declared after 9/11 led to long wars in Afghanistan and Iraq, the use of drone strikes, the detention centre at Guantánamo Bay and controversies over torture and mass surveillance. Air travel changed for good, with reinforced cockpit doors, stricter screening and limits on liquids. For many people around the world, the images of the burning towers remain among the most memorable of their lifetimes.

By the numbers

Timeline

• 1996, August: Osama bin Laden issues his first declaration of war against the United States from Afghanistan.
• 1998, 7 August: Al-Qaeda bombs the US embassies in Nairobi and Dar es Salaam.
• 2001, 11 September, 8:46 a.m.: American Airlines Flight 11 hits the North Tower of the World Trade Center.
• 2001, 11 September, 9:03 a.m.: United Airlines Flight 175 hits the South Tower.
• 2001, 11 September, 9:37 a.m.: American Airlines Flight 77 hits the Pentagon.
• 2001, 11 September, 9:59–10:28 a.m.: The South Tower collapses, followed by the North Tower; Flight 93 crashes near Shanksville at 10:03.
• 2001, 12 September: NATO invokes Article 5 for the first time.
• 2001, 7 October: US and British air strikes on Afghanistan begin.
• 2004, 22 July: The 9/11 Commission publishes its final report.
• 2011, 2 May: Osama bin Laden is killed in Abbottabad, Pakistan.

Why it matters

The September 11 attacks showed that a small, stateless network could inflict mass casualties on the world’s most powerful country. The American response, from the wars in Afghanistan and Iraq to new security systems at every airport, defined the first two decades of the 21st century and still shapes debates about security, liberty and foreign intervention.