Rock Islands of Palau

Declared a marine national park in 2012 and a UNESCO World Heritage Site the same year, the Rock Islands Southern Lagoon of Palau is an archipelago of more than 400 limestone islets undercut by the waves at their base, forming rock mushrooms crowned with dense tropical vegetation on a sea-carved pedestal. Its most distinctive attraction is Jellyfish Lake, a marine lake cut off from the ocean thousands of years ago, where a population of golden jellyfish evolved with no predators until they all but lost the ability to sting, letting visitors swim among millions of them with no risk at all — an evolutionary phenomenon documented in very few places on the planet.