Was it really collapses we saw on TV september 11 2001?

Was it really because of the planes impact and the following fires that World Trade Center 1, 2 & 7 came to the ground?
Or did they in fact explode from top to bottom?

It all happaned very fast.
The Twin Towers were 417 meters tall - 63,5 x 63,5 meters wide - and were more or less pulverized in approximately 12 seconds.

Critics of the official account claim this is equivalent to free fall speed. That would mean zero(0) restistance from the buildings own steel and concrete structure on the way down. Zero.

But the Twin Towers were supported by a core of 47 massive steel beams and 236 on the outer sides.
Could really this fast and total demolition be possible without some kind of explosives?

The video and photographic evidence show something that does not at all resemble collapses! You can see hundreds of thousand tons of concrete and steel beams being thrown like confetti several hundred meters to the sides and up in an arch - as the towers are being pulverized.