Hoyo Azul was definetley the highlight of my travels to Punta Cana, it is a natural fresh water lagoon with cool blue waters! There is a small trail leading up to the enclosed water hole where you pass native Dominican vegatation and some wildlife, birds and butterflies mostly! Once you reach the cliff after a 20 minute hike you reach a breathtaking view of crystal clear waters. The water varies from 2 feet to 40 feet! I stayed pretty close to the surface. I would say if you love nature and only do one excursion while in the Punta Cana area, Hoyo Azul (Blue Hole) is the one to do. The memories will stay with me a lifetime.