The Marieta Islands exist just off the coast of Puerto Vallarta in Mexico. They are said to have been formed centuries ago due to volcanic activity and are uninhabited by people. Just an hour long boat ride from the coast of Puerto Vallarta will see you to these islands, which are sure to floor you in their sheer physical beauty and splendor. Military testing in the early 1900s is said to be the cause of the incredible caves that exist there today, but after the push from infamous scientist, Jacques Cousteau, in the 1960s, the site is now a registered national park. When you visit the Marieta, you can swim through a water tunnel leading you to the elusive hidden beach. It’s not an underwater tunnel, however, so you won’t need to hold your breath… but it’s guaranteed that this site will take your breath away.