This tiny, remote Colombian island has some of the best diving in the world. A World Heritage site, it's a mere 1643m long and 727m wide, and is 378km from the mainland. It's the center of the vast Santuario de Flora y Fauna Malpelo, the largest no-fishing zone in the Eastern Tropical Pacific, which provides a critical habitat for threatened marine species.

The diversity and, above all, the size of the marine life is eye-popping, and includes over 200 hammerhead sharks and 1000 silky sharks. It is also one of the few places where sightings of the short-nosed ragged-tooth shark, a deepwater shark, have been confirmed. The volcanic island has steep walls and impressive caves.

Dive conditions can be treacherous and accidents are not unheard of. Only advanced divers with experience should attempt this trip.

A contingent of soldiers guard Malpelo, and it's forbidden to set foot on the island.