Top Secret Beaches

Four friends scale the cliffs above Cala Luna to take a spectacular dip into Sardinia's blue seas. Meanwhile, in Brazil, another group hunts down a remote beach with world-class snorkeling only available a few hours a day. Then, adventurers head to Costa Rica to hike through the jungle and across crocodile-infested waters to frolic on a beach that's only visible during low tide.

A daring drop through a crack in a 140-foot rock wall reveals Brazil's most isolated beach, while in Sardinia a 45-minute hike leads to a tiny patch of sand surrounded by pink granite and warm turquoise waters. Then, outside San Francisco, a scramble down steep shale rock offers a fantastic view of a waterfall cascading directly into the ocean.