Comment: Explosives at the base wouldn't explain what we saw

(See in situ)

In reply to comment: I'm glad a summary like this (see in situ)

Explosives at the base wouldn't explain what we saw

The tower floors start collapsing just as the debris from above lands on them.

For explosives to have been involved, they would have had to have gone off just as the debris from above hit the floor they were on. And these explosives would have had to have also not been triggered prematurely by the intense heat of the burning jet fuel.

Steel structures are built to support the floors above them. Not to have the floors above them dropped on them from 10's of meters above.

It's also worth noting that the the towers were built less robustly than most steel structures, with increased office space at the expense of a huge internal area with no support.