Collapse of the World Trade Center — collapse of the World Trade Center in New York City on September 11, 2001
The deliberate destruction of the Twin Towers killed nearly 3,000 people and remains the deadliest single terrorist act targeting a building in world history.
Key Facts
- Immediate death toll
- 2,760 people
- Total deaths at site
- ~3,000 people
- North Tower collapse time
- 10:28 a.m., after burning 1 hr 42 min
- South Tower collapse time
- 9:59 a.m., after burning 56 min
- Tower height
- 110 stories — tallest freestanding structures ever destroyed
- 7 WTC collapse
- 5:21 p.m., same day, due to debris-ignited fires
By the Numbers
Location
Cause → Event → Consequence
Al-Qaeda operatives hijacked two commercial airliners — American Airlines Flight 11 and United Airlines Flight 175 — and deliberately crashed them into the North and South Towers of the World Trade Center. The impacts severely damaged fire insulation at the strike zones, allowing temperatures to rise until the towers' steel structures were critically weakened, triggering progressive collapses.
At 8:46 a.m. on September 11, 2001, Flight 11 struck the North Tower; at 9:03 a.m., Flight 175 struck the South Tower. Both 110-story towers underwent total progressive collapse, at 9:59 a.m. and 10:28 a.m. respectively. Later that afternoon, the debris-damaged 7 World Trade Center also collapsed, and four other adjacent structures were destroyed or severely damaged.
Nearly 3,000 people were killed at the site, and toxic dust from the destroyed towers caused long-term health effects for thousands in the vicinity. The cleanup cost hundreds of millions of dollars and ran around the clock. Surrounding damaged structures required demolition, and construction of the replacement One World Trade Center proceeded for over a decade, opening in 2014.