The document summarizes the construction and history of the Twin Towers of the World Trade Center in New York City. It describes their construction from 1966-1973 at a cost of $1.5 billion and completion. On September 11, 2001 Muslim terrorists hijacked and crashed commercial airplanes into the towers, collapsing them and killing nearly 3000 people in a coordinated terrorist attack. The event marked a major tragedy and changed security and policy in the United States.