World Trade Center (2001–present)
The buildings are among many created by the World Trade Centers Association. The original World Trade Center featured the landmark Twin Towers, which opened in 1973, and were the tallest buildings in the world at the time of their completion. They were destroyed on the morning of September 11, 2001, when al-Qaeda-affiliated hijackers flew two Boeing 767 jets into the complex in a coordinated act of terrorism. The attacks on the World Trade Center killed 2,753 people. The resulting collapse of the World Trade Center caused structural failure in the surrounding buildings as well. The process of cleaning up and recovery at the World Trade Center site took eight months, after which rebuilding of the site commenced.
September 11 attacks
Immediately after the attacks, the Federal Bureau of Investigation started PENTTBOM, the largest criminal inquiry in the history of the United States. At its height, more than half of the FBI's agents worked on the investigation and followed a half-million leads. The FBI concluded that there was "clear and irrefutable" evidence linking al-Qaeda and bin Laden to the attacks.
The FBI was quickly able to identify the hijackers, including leader Mohamed Atta, when his luggage was discovered at Boston's Logan Airport. Atta had been forced to check two of his three bags due to space limitations on the 19-seat commuter flight he took to Boston. Due to a new policy instituted to prevent flight delays, the luggage failed to make it aboard American Airlines Flight 11 as planned. The luggage contained the hijackers' names, assignments, and al-Qaeda connections. "It had all these Arab-language papers that amounted to the Rosetta stone of the investigation", said one FBI agent. Within hours of the attacks, the FBI released the names and in many cases the personal details of the suspected pilots and hijackers. On September 27, 2001, they released photos of all 19 hijackers, along with information about possible nationalities and aliases. Fifteen of the men were from Saudi Arabia, two from the United Arab Emirates, one from Egypt, and one from Lebanon.