Islas Marietas

A small volcanic archipelago off the coast of Nayarit in Banderas Bay, the Marieta Islands are designated a national park and UNESCO-recognized biosphere reserve. The islands contain sea caves and a secluded beach enclosed within a collapsed volcanic crater — accessible only through a water tunnel that must be swum through at low tide. Blue-footed boobies nest on the rocky surfaces, and the waters around the islands are a protected marine habitat for manta rays and sea turtles.