13-ThinkstockPhotos-512535734.jpg

Thinkstock

Exploring underwater caves can be an incredible experience, but you should be properly trained and it’s best to travel with a guide. It is especially dangerous because if something were to happen, the diver cannot swim vertically up to the surface because of the surrounding cave. Some of the best places to go cave diving in the U.S. are Devil’s Cave System in Ginnie Springs and Merritt's Mill Pond in Florida.