Let’s say, hypothetically, that while vacationing in Puerto Vallarta, you get tired of sitting on the beach, cruising the Malecón, or eating tacos that are so freaking good and cheap you find yourself crying into your Pacifico. Hypothetically speaking. Lucky for you, you can take a short boat trip to Islas Marietas, a group of small, uninhabited islands teeming with marine life. Strap on a snorkel mask and dive directly off the side of your boat. But seriously, strap on a snorkel and make sure the boat is in the sea first. Sea turtles, manta rays, octopi, wild dolphins, and humpback whales all call the waters surrounding the volcanic islands home. And when the tide is right, you can snorkel to a hidden beach inside a hollowed-out cave with a massive natural skylight. That beats cramming down more tacos and beers -- but just barely.