4 World Trade Center
The September 11th Attack
WTC 4 was a nine-story building that stood directly east and southeast of the South Tower (WTC 2). The building had six tenants, with most of its floors being occupied by Deutsche Bank and the New York Board of Trade.
Evacuation
Apparently the evacuation of Building 4 began shortly after the North Tower was hit.
Damage
WTC 4 was severely damaged by fallout from the collapse of the South Tower, with all but one wing of the building having collapsed to ground level.
Fires
The portion of WTC 4 that remained standing had a blackened appearance suggesting that it sustained severe fires. However, FEMA's Report does not describe the fires in WTC 4, though it devotes much of the chapter on WTC 4, 5, and 6 to fires in WTC 5. Despite the crushing of most of WTC 4 by fallout from the Towers, it does not appear that the fires caused any further collapse of this building.
Destruction
WTC 4 was demolished as part of the clean-up of Ground Zero. WTC 4's basement housed precious metal vaults, the apparent disappearance of most of whose billion-dollar contents has gone curiously unreported.