Cleanup of the World Trade Center site (colloquially “Ground Zero”) took eight months and was completed in May 2002, while the Pentagon was repaired within a year. After delays in the design of a replacement complex, construction of the One World Trade Center began in November 2006; it opened in November 2014. Memorials to the attacks include the National September 11 Memorial & Museum in New York City, the Pentagon Memorial in Arlington County, Virginia, and the Flight 93 National Memorial at the Pennsylvania crash site.
The origins of al-Qaeda can be traced to 1979, when the Soviet Union invaded Afghanistan. Osama bin Laden traveled to the country to volunteer, viewing the war as a holy cause to help fellow Muslims (in Afghanistan) defeat Communist invaders (the Soviets). Bin Laden organized fellow Arab mujahideen (the “Afghan Arabs”) to resist the Soviets until that country’s exit from Afghanistan in 1989. The U.S. Central Intelligence Agency (CIA) funneled several billion dollars worth of weapons to the indigenous Afghan mujahideen resistance, a portion of which bled to the Arab volunteers. However, no direct U.S. aid to bin Laden or any of his affiliates has ever been established.
