Los Arcos, two arching granite rock formations just off Playa Mismaloya, have been the symbol of Puerto Vallarta since John Huston filmed "Night of the Iguana" nearby. A protected underwater park since 1984, they are a favorite destination for snorkeling, scuba diving and day cruises. Depth of the crystal waters here is between 30 and 1,600 feet (9-480 meters).