Donald Rumsfeld
The United States was attacked on September 11, 2001 by al Qaeda terrorists who hijacked commercial airliners and crashed them in coordinated strikes into both towers of the World Trade Center in Lower Manhattan, New York City and the Pentagon in Washington, D.C. The fourth plane crashed into a field in Shanksville, Pennsylvania, and its target was likely a prominent building in Washington, D.C., most probably either the Capitol Building or the White House. Within three hours of the start of the first hijacking and two hours after American Airlines Flight 11 struck the World Trade Center, Rumsfeld raised the defense condition signaling of the United States offensive readiness to DEFCON 3, the highest it had been since the Arab-Israeli war in 1973.
Mahmoud Mahmoud Atta
Following the September 11, 2001 attacks in the United States it was initially thought that Mahmoud Mahmoud Atta was one of the hijackers on board the first plane to hit the World Trade Center. This led to the harsh questioning of US immigration authorities and the intelligence community, because it was felt that they had failed to stop a known terrorist from entering the country under his true name. However, his identity was confused with the Egyptian militant leader Mohamed Atta who was actually on board the flight.