The post includes A Brief History of Time (1992) about Stephen Hawking and Bed Peace (1969), John Lennon and Yoko Ono's protest of the Vietnam War, to Billie Holiday: The Life and Artistry of Lady Day (2002) and Audio Ammunition, a web site devoted to short documentaries.
There are items by or about some of the best in the business including David Lynch and Alfred Hitchcock. The world's most (in)famous from the music industry are also represented including Bob Marley, Lou Reed and The Ramones. Look at new films, old films, how-to films (Disney animation), silent films, music films. There is enough there to keep you interested for a while.
Documentaries let us examine the real world through the filmmaker's lens. They let us see the past, albeit filtered through the camera, our current world, and possibilities for the future. What was the last documentary you watched?