Destroyed by fire
The twin towers experienced massive structural damage. Even so, they stood up for two hours, allowing thousands of people to escape. But eventually the buildings collapsed. Ultimately, fire destroyed them.
The jets' impacts destroyed exit stairs, broke the towers' sprinkler systems and knocked fireproofing off floor beams.
| 
The World Trade Center.
Skidmore, Owings and Merrill LLP |
|
