Chinchorro Bank, Mexico
Last August, Hurricane Dean blasted through the Yucatán Peninsula, nearly destroying Mahahual, the tiny fishing village that serves as the diving gateway to Chinchorro Bank—one of the largest and least visited atolls in the Caribbean. The good news is that Chinchorro, a 30-mile-long, brightly colored hard-coral reef, was left unscathed, and Mahahual's dive operators have made a valiant comeback. "In Cozumel there can be 2,000 divers a day," says Marco Martin, president of Mahahual's Dreamtime Dive Resort. "We rarely see other divers."

Chinchorro's 20-foot-deep limestone shelf is covered with orange elephant ear sponges that attract baitfish and big tarpon. The reefs have also claimed their share of ships; the shallows are a graveyard of rusting freighters, many of which are visible to snorkelers on the surface.

GO WITH: Dreamtime Dive Resort; $180 for three dives at Chinchorro, plus $25 gear rental; dreamtimediving.com

STAY: Three miles south of Mahahual at Balamku, a wind- and solar-powered beachfront resort with Maya-inspired design. Palapa number six has the best view. Doubles, $85; balamku.com