Physicists, engineers, architects, researchers, intelligence experts, and then some. These are more symposium talks presenting scientific data than "documentaries" - no drama or effects. No far flung theories here, just questions:
Physicist Steve Jones:
https://youtube.com/watch?v=aMhl-S5MyAc
David Ray Griffin
http://video.google.com/videoplay?do...c h&plindex=5
9/11 Re-visited (features mostly scientific testimony)
https://youtube.com/watch?v=PWgSaBT9hNU
Press For Truth (family of victimes pressure the administration to investigate)
http://video.google.com/videoplay?do...arch&plindex=2
Oil, Smoke & Mirrors (documentary):
http://video.google.com/videoplay?do...arch&plindex=9
Interview on British Television with David Shayler (British Intelligence):
http://video.google.com/videoplay?do...arch&plindex=6
Kevin Ryan, of Underwriters Laboratory
http://video.google.com/videoplay?do...arch&plindex=0
Richard Gage
http://video.google.com/videoplay?do...arch&plindex=0
NYC Firefighter testifies about what happened that day
http://video.google.com/videoplay?do...arch&plindex=7
William Rodriiiguez speech:
http://video.google.com/videoplay?do...arch&plindex=0
A compilation of the various experts who talk science, and research, rather than conjecture or fantasy:
http://video.google.com/videoplay?do...arch&plindex=1