Video uploaded 23 years after tragic event shows numerous white flashes as towers collapse, presumed to be thermal charges which are mostly used in controlled demolitions

Previously unreleased footage shows the moment the World Trade Center Twin Tower buildings in New York City collapsed nearly an hour after being hit by commercial airliners.

The never-before-seen footage uploaded 23 years after the terror attacks shows the towers engulfed in smoke shortly before they fell in free-fall into their own footprints, much to the horror of New Yorkers and onlookers across the globe.