Dive into a shark buffet.
Credit: Stephen Frink / Getty Images

You don't just scuba Tiputa Pass; you surf it, riding the high-speed tidal surge as the vast blue South Pacific pours into the Rangiroa atoll's lagoon through the 300-yard-wide pass. All that aquatic chaos gongs a gigantic dinner bell for the family Carcharhinidae. White-tips, black-tips, lemon, and tiger: They gather at the mouth of the pass by the hundreds - glowering, prowling, relentlessly circling, a living tornado of predators. It is one of the world's great gatherings of underwater wildlife. Hanging on to a jut of rock, you might well wonder why you aren't torn to chum. It's simple: The menu is just too extensive, and you just aren't that tempting. You surf right through the whole food chain, relatively indigestible and thoroughly amazed. [$190 for a two-tank dive; TOPDive Rangiroa]

More information: Rangiroa is an hour's flight from Tahiti on Air Tahiti Nui.