At 8:46 a.m. on September 11, 2001, hijackers crashed American Airlines Flight 11 into the north tower of the World Trade Center in New York City. Six minutes later, the first contingent of New York City firefighters—two ladder and two engine companies—had arrived at the stricken building. They had just begun to climb a stairwell in an effort to reach people trapped on the upper floors, when another hijacked airliner, United Airlines Flight 175, struck the south tower at 9:03 a.m. More.
How 9/11 Became the Deadliest Day in History for U.S. Firefighters