We did the Atlantis Submarine in St. Thomas. It was interesting, but I don't think I would do it again. It can get claustrophobic with all those people crammed into a small place. And I guess I was expecting it to be really colorful down there, but it was mostly brown. You do learn a lot of interesting facts and the guide was really funny. My favorite part of this excursion was the boat ride to and from the submarine. We rode up top--what a blast!