Have you ever wanted to do a real cave dive, but you are not cave certified?  Here is your chance.  Bonne Terre Mine Missouri, is 60 miles south of St. Louis. 

Depths to: 100 feet (30 m); the average depth being 40-60 feet (12-18 m)

Visibility: Exceeds 100 feet (30 m)

Water temperature: 58 degrees Fahrenheit (14 degrees Celsius) year-round. A 7 mm wet suit or a dry suit is recommended.
So check out the video and enjoy your cave experience.

http://www.youtube.com/watch?v=QIa4lJWLK34&usg=AL29H21y2bsqeQ8S2kNEeO_HEwTiRb6zTQ