A documentary about the 8000 year history of Tehran have been created by ChasmiDigar (http://www.chashmidigar.com/). I think this history is unknown to many people.

Here are two short 3 min clips from the documentary, they're both in part English part Persian (the most important parts are in English) :

http://www.iranian.com/ram/Clips/tehran1.ram
http://www.iranian.com/ram/Clips/tehran2.ram

Unfortunatly, the website of ChasmiDigar (http://www.chashmidigar.com/) isn't workin properly and the clips are very short. :(