I came across this cool project to visit every lat-long confluence in the world. Theyve since whittled it down to needing land to accept pics, but we being divers, I figured land is only a matter of depth. Id be interested in helping out with the north florida points if anyone has a boat. The panama city and st marks ones are pretty close and not too deep.
http://www.confluence.org/index.php
http://www.confluence.org/index.php