Here is a photo compilation from Gremlins Research which shows the official explanation from the National Institute for Standards and Technology, for why World Trade Centre Building Seven......Disappeared. lol.
PDF 28 Photo Comp 1 NIST SUM UP
Watch this great video below for a compilation of so many subjects related to 9/11. Skip to 5m15s into the video for some great clips referring to explosions of some kind. It's over 2 hours long!
Please listen to William Rodriguez at 7m23s!!!
He was an employee at the Twin Towers for over 20 years and he passionately describes the bomb that went of in the basement or the lower floors before the 1st plane hit the tower! This includes seeing people with their skin hanging off their face and body.