This video made the viral-Internet rounds about two years ago, but I'm only just now getting around to seeing it since it was recommended by the videographer Philip Bloom as an example of how even a one-man show used to do weddings can still shoot/produce a breakout piece of work. So here is the movie, all riveting 40 minutes of it.
In this video filmmaker Andrew Wonder followed around urban explorer Steve Duncan as they illegally ventured into subway tunnels, sewers, bridges in Manhattan. It's suspenseful and thrilling and informative at the same time. I particularly appreciate the interviews they got with various street folks. We've all heard about the "mole" people living underground, here is your chance to learn a little more about what that might be like.
Also, this is a good example of how the form factor of the Video-enabled DSLR's really let you get into tight, tight places and shoot without being to conspicuous, even in low light, without too much loss of quality.