On September 11, 2001, 2,977 people were killed in the deadliest terrorist attacks in American history. Two planes, hijacked by Islamic jihadists vowing death to all Americans, plowed into both towers at the World Trade Center in New York. Another plane was flown into the Pentagon in Washington, DC. A fourth plane, presumably headed for the White House or the U.S. Capitol, was heroically diverted by passengers and ended up crashing in an empty field in Pennsylvania.
--from Miller Center (UVA)