Day of Disaster
Day of Disaster is a video by Steve Spak containing video footage of ground zero immediately after the attacks. This includes some pictures of smoke and flames in WTC7, making it of particular interest to 9/11 researchers.
Originally sold commercially, Spak donated the footage to Archive.org, where a DVD ISO image file could once be downloaded here, free of charge.
That's now been removed, though, and Day of Disaster appears to be a commercial product again, available at Amazon.