Galapagos is world central for weird and plentiful wildlife. And that goes for what's under the water as well as what's hanging out on the dry part of these volcanic islands. And when it comes to sharks, you're in for a special treat.

Liveaboards are the way to go—the best shark viewing is off Wolf and Darwin Islands, a good boat ride from the Galapagos’ main islands. Throngs of shark species roam these waters; silky, white tip, scalloped hammerheads, and whale sharks give divers quite an evolutionary show.

Hammerheads are, perhaps, the ultimate experience. Immense schools of them circle underwater peaks, possibly drawn by electromagnetic patterns. This is not an experience of one or two big sharks—it’s an experience of sharks as far as the eye can see.