Add a hundred tons of aluminium and jet fuel to a confined steel structure and cover it in dust and office debris, then set light to it...
The aluminium melts and gets hot enough to turn steel into a caramel paste. at this point, the top of the building collapses, causing the entire structure to collapse under its own weight.
Two independent, (from the state and each other), engineers concluded that contrary to the official report the aircraft were largely intact rather than shredded when they entered the towers, and allowing for this they concluded that molten aluminium draining down the vertical structure of the building was enough to incinerate the fireproof membrane and allow the heat to soften the steel. The rest as they say, is history.
Goole aluminium recycling plant explosions if you don't believe it...
Unfortunately, the New York Port Authority, the agency responsible for sorting and disposing of the debris, refused to release so much as an ounce of 9/11 debris for them to test their findings. Make of that what you will.
There have been several very informative, independent documentaries dispelling most of the 9/11 bullshit.
The only questions left unanswered are exactly how much was known prior to the event and why was nothing done. Between Michael Moore, various enquiries and independent reports, the afters have been done to death.
As for CIA torturing people, right or wrong they did what they did, and it was known if ignored by everyone... remember the CIA transit stops at Prestwick a few years ago? This is not news.
The only people who have lost out in the whole debacle are the US. Someone in the CIA or NSA wanted the Patriot Act implemented, and allowing 9/11 to happen was the impetus that was needed.