Secrets & power · New York, Washington, Pennsylvania · 11 September 2001

9/11: What the Investigations Found

Established2001 CE – 2008 CELower Manhattan, New York, USA

Two official investigations reconstructed the attacks in detail. The alternative theories that followed have not held up.

On 11 September 2001, nineteen al-Qaeda hijackers took over four airliners. Two struck the World Trade Center towers, one hit the Pentagon and one crashed in a field near Shanksville, Pennsylvania, after passengers fought back. The attacks killed 2,977 people: 2,753 in New York, 184 at the Pentagon and 40 on Flight 93. The 9/11 Commission's 2004 report documented the plot and the intelligence failures that let it succeed.

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EstablishedSupported by strong, converging evidence.

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Hero image: The Tribute in Light memorial over Lower Manhattan, 2010. Photo: U.S. Air Force (Sgt. Randall A. Clinton) · Public domain · via Wikimedia Commons. Evidence labels describe the written claims, not the image. Version 1 · updated 2026-10-22.