America Under Attack: Anatomy of a collapse

North Tower | 10:28 a.m. : FINAL MOMENTS
The exterior walls buckle. Driven by 45,000 tons above, the floors pancake, progressively collapsing the tower from within. Several floors remain standing like a jagged stump but later collapse.

North Tower | POSTMORTEM
The north tower stood for 102 minutes. It crumples to the ground in eight seconds. The impact of the collapse was equal to a 2.0 magnitude earthquake.

Intro | North Tower |South Tower | Pentagon

GRAPHICS BY DOUG STERN - USN&WR
REPORTING BY AVERY COMAROW, DAVID LAGESSE, AND KENNETH TERRELL-USN&WR