25 minutes later at 10.28 a.m. nearly 1000 people were still trapped in the upper 20 floors of the North Tower, together with many firemen unaware of the evacuation order and still inside the tower trying to save people. At this moment the North Tower came down. The theory for the collapse is that the tense fire had weakened the bare steel of the core columns and this had caused the building to start pancaking down similar to a situation in controlled structure demolishing. In total 2800 people died in the attack, 479 of them were from the emergency services including 343 firefighters.