Cenote Zapote (Hells Bells)
An hourglass-shaped sinkhole about 26 km west of Puerto Morelos, famous for the 'Hells Bells': bell-shaped calcite formations up to about 2 m long that hang from the walls between roughly 28 and 38 m. Research shows they form in a thin redoxcline just above the halocline, where a turbid sulfidic layer sits at about 35–37 m. The cenote bottoms out at around 54–55 m, and a tree trunk rises from the bed. It is a deep, dark dive rather than a classic shallow cavern tour.
Facts
- Region: Mexico – Riviera Maya Cenotes
- Area: Puerto Morelos – Ruta de los Cenotes
- Depth: 0–40 m
- Level: advanced
- Current: low
- Type: cave
- Coordinates: 20.85772, -87.12665
- Highlights: Hells Bells: bell-shaped calcite speleothems at ~28–38 m, hourglass-shaped sinkhole, hydrogen sulfide / turbid redoxcline layer at ~35–37 m, halocline top at ~36.6 m, total depth ~54–55 m with an ancient tree trunk on the bottom, low-light environment
- Tips: Operators run it as a deep guided dive and require Advanced Open Water (or equivalent) plus good buoyancy and comfort in overhead/low-light settings; max ~4 divers per guide is typical. Note the bells lie at 28–38 m, deeper than the 21 m cavern-zone depth limit in Mexico's NOM-09-TUR-2002, so plan it as a deep dive and stay with the guide. Any penetration into dark passages is full-cave territory and needs cave certification. Entrance is paid at the ecopark; operators usually include it (check current).