As mentioned above, the helmets become nearly weightless underwater, but help keep you down there. You go down a ladder and, at least where we were, you walk on sand along a roped path. Partway through, one of the leaders feeds some fish for fun photo ops. After looking at a couple of rocks or landmarks (natural??), up the ladder you go and a hook lifts your helmet off and you survive. It was fun for us with our son and his family. I like to snorkel, so this was a unique experience...while under I kept looking for Captain Nemo and the Nautilus.