The Captiva Blue Hole or The Crack as sometimes called locally, is geologically a sinkhole and a very popular diving and fishing location. The rim of the hole is about 95 feet deep and drops down to 180 feet. Lots of Snapper and Grouper. Amberjack and Barracuda frequenty hang out above the hole.
Video of a dive on the hole:
Only registered users may download. Registration is free.