The collapse of WTC 7 shows many signs of controlled demolition.

First, this 47-story skyscraper, its height about five times its depth, dropped directly into its footprint in a smooth, vertical motion. The symmetry of WTC7's collapse meant that this Building's 58 perimeter columns and 25 central columns of structural steel must all have been shattered at almost the same instant.

Building 7 remains centered around its vertical axis as it falls.

Controlled demolition is required to achieve vertical collapse of structures much less tall than Building 7.

Second, WTC 7 collapsed completely in less than 7 seconds, a time almost equal to that of unimpeded free-fall. If a brick were dropped from 570 feet—the height of Building 7's roof—in a vacuum, it would hit the ground in 5.95 seconds. Thus, the building's falling mass encountered almost no resistance, showing that its structure had been destroyed before it fell.

This montage is composed of slices of frames from a CBS video of Building 7's collapse. The slices are separated by one-second intervals. The distance from the top of the intact building to the top of the logo is about 400 feet.