Twenty-five years ago today, the United States experienced the deadliest terrorist attack in its history when al-Qaida hijackers commandeered four commercial airliners and turned them into weapons, killing nearly 3,000 people in a span of roughly 102 minutes. The attacks unfolded in a precise, devastating sequence beginning in the early morning hours of Sept. 11, 2001, and the exact timeline remains one of the most studied chronologies in modern American history.

All times below are in Eastern Daylight Time, matching the time zone in which the attacks occurred.

The hijacked flights take off

The morning began ordinarily. American Airlines Flight 11, a Boeing 767 carrying 92 people, departed Boston's Logan International Airport at 7:59 a.m., bound for Los Angeles. United Airlines Flight 175, also departing from Boston and headed to Los Angeles, took off shortly afterward at 8:14 a.m. American Airlines Flight 77 left Washington Dulles International Airport at 8:20 a.m. en route to Los Angeles, and United Airlines Flight 93 departed Newark International Airport at 8:42 a.m., also headed for the West Coast. All four aircraft were hijacked within the first hour after takeoff.

First impact: North Tower

At 8:46 a.m., Flight 11 crashed into the North Tower of the World Trade Center, striking between the 93rd and 99th floors. The impact killed everyone aboard the aircraft and hundreds of people inside the building instantly. Initial news coverage in the moments afterward described the event as........

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