The World's Most Deadly Terror Attacks

Flames spew out of 2 World Trade Center after it is struck by a commercial airliner in a terrorist attack, Sept. 11, 2001 in New York. A hijacked American Airlines Boeing 767, originating from Boston's Logan Airport, struck 1 World Trade Center (north tower) at 8:45 a.m. At 9:03 a.m., a United Airlines 767, also hijacked in Boston, crashed into 2 World Trade Center (south tower). Both towers later collapsed. Nearly 3,000 people died in dual attacks on Washington and New York City, the worst terrorist act on U.S. soil. (David Handschuh/New York Daily News Archive via Getty Images)