Three Hours That Shook the World: Observations on Intolerance is an interview with Kevin Brownlow which includes occasional clips and stills from the film. He has a ton of fascinating anecdotes about the film and its participants, including a really funny story involving David Shepard, another vaunted name in silent film, and Intolerance's editor, James Smith.
Credits
Three Hours That Shook the World: Observations on Intolerance Cast
Three Hours That Shook the World: Observations on Intolerance Crew