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.