Blue Hole Natural Monument

The Great Blue Hole is a flooded Ice Age cavern in the middle of Lighthouse Reef Atoll, a near-perfect circle some 300 m across and roughly 124 m deep, its rim ablaze with reef and its depths hung with giant stalactites. Declared a natural monument in 1996 and part of the Belize Barrier Reef Reserve System World Heritage site, it is co-managed by the Belize Audubon Society. The classic dive is a brief, deep excursion along the wall to the stalactite gallery at about 40 m, watched by Caribbean reef sharks, before a long shallow finish on the rim; day trips pair it with Half Moon Caye Wall and Long Caye Aquarium.

The rules that bind divers

Visitors pay a protected-area fee to the Belize Audubon Society, collected by tour operators, and dive or snorkel only with licensed guides. The site's depth sets the practical rules: the stalactite dive is for experienced divers, briefed hard on depth limits, narcosis, and short bottom times, while others snorkel the rim. Boats use designated moorings on the rim (anchoring into the reef is prohibited), and fishing or collecting inside the monument is banned. Nearby Half Moon Caye, also Audubon-managed, carries its own fee and seabird-colony restrictions.

Fees & permits: Per-person protected-area fee for the monument (plus a separate Half Moon Caye fee on combined trips), normally included by operators.