Image by Olivier Blaise Getty Images

Snorkelling in Jellyfish Lake is one of Palau's many highlights. This land-locked marine lake, in the south of the archipelago, is filled with millions of harmless transparent jellyfish that swim en masse to follow the path of the sun. Floating among these pulsating creatures – which expand and contract hypnotically – is like exploring the atmosphere of an alien world.

From where the boat moors, you'll need to hike up over a hill about 10 minutes through the jungle to reach this mangrove-bordered lake – be careful of the slippery rocks.