I find it funny that there's all these people out there that think there was some kind of government conspiracy around 9/11, it's just as ridiculous as the people who think the Moon landing was faked in a studio.
Yeah the government found out that terrorist planned on crashing planes into the twin towers so they put explosives in the towers to make sure they would collapse, because simply having terrorist fly planes into them wouldn't have been enough.
Think about how paranoid that sounds.