The world trade center destruction was caught live on TV for millions to see, yet the conspiracy theorists even go as far to say that this was faked in one way or another.
The most common ‘evidence’ brought forward for foul play is the uniform destruction of the WTC Twin Towers, the pancaking effect. Where the Twin Towers collapse was uniformly flat down. Some conspiracy theorists think this is evidence for a controlled destruction, where much the same technique is used with controlled explosions. This picture shown below is used to prove the existence of explosives:
Yet this can be easily explained.
All skyscrapers are built with an engineering auto destruct sequence in them, so if anything serious happened to the building, it wouldn’t take out half of New York when it fell over. This pancaking effect is built into the building.