I'm not sure how many have seen this before but I thought it was a pretty big eye opener, photos of a 600mm f/4 being retrieved from a crocodile infested swamp. Apparently, the guy was shooting from a bridge, with the 600 on a monopod with a 2x. The head snapped, with the lens hitting the concrete bridge, then rolling off, straight into the water!
Photos:
http://www.timaustinimages.com/p9856...6CFB#685206779
http://www.timaustinimages.com/p9856...6CFB#861584172
the thread:
http://photography-on-the.net/forum/...d.php?t=451992.