former building complex in lower Manhattan, New York City, consisting of seven buildings and a shopping concourse on a 16-acre (6.5-hectare) site; it was destroyed by a terrorist attack on Sept. 11, 2001. Prior to its destruction, the World Trade Center had been the world's largest commercial complex, home to many businesses, government agencies, and international trade organizations. Most prominent among its structures were the 110-story rectangular twin towers, one rising to 1,362 ft (415 m) and the other to 1,368 ft (417 m), with floors roughly an acre in size. Designed by Minoru Yamasaki and Emery Roth, the towers and concourse portion of the center were completed in 1973 at a cost of some $750 million. For a brief period (until the completion of the Sears Tower, now the Willis Tower, in Chicago in 1974), the World Trade towers were the tallest buildings in the world. They remained the largest structures on the Eastern Seaboard of the United States, an internationally known landmark and tourist attraction rising high above the skyline of lower Manhattan.
In 1993 a terrorist car-bomb explosion damaged portions of the complex, killing six people and causing more than $300 million in damage. Sheik Omar Abdel Rahman and nine other Islamic extremists were convicted of conspiracy and other charges related to the bombing in 1993, and the so-called mastermind, Ramzi Yousef, was convicted in 1998. On Sept. 11, 2001, a second terrorist attack, in which two hijacked commercial jetliners were crashed into the towers, ignited huge, intense fires in the upper stories of both buildings, weakening them and leading to their collapse. Other structures in the complex were completely or partially destroyed as a result, and many surrounding buildings were severely damaged. More than 2,700 people, including the passengers and crew of the airliners and several hundred emergency personnel responding to the initial fires, lost their lives; more than 7,000 people were injured.
The enormity of the events of Sept. 11 (see also 9/11), which also involved a similar attack with a hijacked jetliner on the Pentagon in Washington, D.C., and the crash in W Pennsylvania of a fourth hijacked plane, galvanized national feeling in the United States, where many watched the events unfold on television. In the aftermath of the worst terrorist attack in history, President George W. Bush announced a war on terrorism, and many nations pledged their support. Al Qaeda, headed by Osama bin Laden, was identified by U.S. authorities as being behind the attacks, and the United States subsequently began military operations in Afghanistan, where bin Laden was based and where the government was closely allied with him.
In Dec., 2001, Zacarias Moussaoui, a Frenchman of Moroccan descent who had been arrested (Aug., 2001) on immigration violations in Minnesota, was indicted on charges that he was part of the conspiracy responsible for the September attacks. He pleaded guilty in 2005 to being part of a conspiracy to attack the White House in a similar manner but denied being part of either Sept. 11 attack, and was given a life sentence in 2006.
The alleged mastermind of the plot was Khalid Sheikh Mohammed, a Kuwaiti of Pakistani parentage who had become a high-ranking member of Al Qaeda. He was captured in Pakistan in 2003, held by the United States at an undisclosed location, and transferred to Guantánamo Bay in 2006. According to a censored transcript of a closed-door hearing in 2007, he admitted to organizing and supervising the execution of the attacks of Sept. 11, but the government also later revealed that he had been subjected to waterboarding, which is generally regarded as a form of torture. In 2008 the Pentagon announced that a military tribunal would try Mohammed and others held at Guantánamo on conspiracy and other charges relating to the attacks; later plans (2010) for a federal trial were abandoned in 2011 in the face of strong political opposition. The five suspects were formally charged in 2012. Bin Laden, who had approved the attacks and eluded capture by U.S. forces in Afghanistan in the months following the attacks, was killed in May, 2011, during a raid by U.S. forces on the house in Abbottabad, Pakistan, in which he was living in hiding.
In the aftermath of the center's destruction, many competing interests—the city and state of New York, the owners of the site, the buildings' developer, survivors of the attack and families and friends of those killed, and others—advocated a variety of approaches to rebuilding the site. After a lengthy design competition, a preliminary master construction plan for the site, by Daniel Libeskind, was approved in 2003. The design has since been much modified, and a new overall plan was unveiled in 2006.
Embracing the ground where the towers stood is a tree-filled street-level plaza that opened in 2011. The towers' footprints are the focus of the memorial; waterfalls stream over sunken black granite walls that edge square voids, feeding two pools below whose centers are smaller, echoing voids; the names of those who died are cut into bronze panels that surround the pools. The plaza was designed by Peter Walker; the memorial by Michael Arad. The plaza also contains the trapezoidal entrance to an underground memorial museum, which opened in 2014. Surrounding the memorial are a group of office towers (not all completed) that rise in height toward the the “Freedom Tower” (One World Trade Center), designed by the American architect David M. Childs of Skidmore, Owings and Merrill and opened in 2014. At 1,776 ft (541 m) high, with 94 floors, it is the tallest building in the United States. Two World Trade Center was designed by England's Lord Norman Foster, Three by another English architect, Lord Richard Rogers, and Four (completed 2014) by Japan's Fumihiko Maki. The complex also includes a transportation hub by Spain's Santiago Calatrava and will include a performing arts center.