Eden Rock & Devil's Grotto

Devil's Grotto hides the best light show in the Caymans a stone's throw from the cruise tenders. The twin coral heads are hollow — a maze of tunnels and chimneys where midday sun drops through ceiling holes in solid-looking columns. In late summer the chambers fill wall-to-wall with silversides, a shifting metal fog through which tarpon cruise like slow torpedoes, scattering channels that heal instantly behind them. The rest of the year the tarpon remain, patient and enormous, over divers threading the swim-throughs. As a shore dive costing a tank and a ladder step, it is close to unbeatable.

The moment you come for: Tarpon gliding through silverside clouds (late summer), sunbeam chambers, world-class shore-dive access.

Topography: Two coral massifs on sand, riddled with connecting tunnels, chimneys, and skylit chambers.

Current: Calm except when winter norwesters send swell onto this coast.

Entry: Ladder and step entries from the George Town waterfront dive centers; a swim of a few dozen meters reaches the rocks.

Hazards: Cruise-tender and boat traffic outside the swim zone; mild overhead in the tunnels — every chamber has visible exits, but stay oriented.

Conservation: Marine-park waters in the island's busiest corner; the grottos survive on good buoyancy and no-touch discipline.