The National Park of Chankanaab, translated as "small sea," consists of a saltwater lagoon, an archaeological park, and a botanical garden, with reproductions of a Mayan village and Olmec, Toltec, Aztec, and Mayan stone carvings scattered throughout. You can swim at the beach, plus there's plenty for snorkelers and divers to see beneath the surface—picture underwater caverns, a sunken ship, crusty old cannons and anchors, and a sculpture of la Virgen del Mar (Virgin of the Sea), all populated by parrotfish and sergeant majors galore. To preserve the ecosystem, rules forbid touching the reef or feeding the fish. You'll find dive shops, restaurants, gift shops, a snack stand, and dressing rooms with lockers and showers right on the sand. Parque Chankanaab also a Dolphin Discovery facility where true Flipper fans can swim with the much-loved marine mammals (wwww.dolphindiscovery.com).