More than 40 million years ago, the Yucatan Peninsula was a thriving coral reef covered by the ocean. The ice ages raising and lowering the level of the ocean, the Yucatan knows periods out of the water and others totally immersed. Today, the study of marine fossils inside the caves helps us understand its history.

The work of time and the elements

Underground caves were formed when the ocean level was low. Rainwater, mixing with carbon dioxide from the atmosphere, creates carbonic acid. As the soil of the Yucatan is made up of very porous limestone, this acid seeped into the ground, dissolving the limestone and over time carving out immense systems of underground tunnels and caves. The dissolved limestone dripping in the passages of dry caves, over thousands of years, has formed an incredibly beautiful decoration of stalactites and stalagmites. It takes about 100 years for one inch of growth.

End of glacial air

After the last ice age about 8000 years ago, the ocean level rose again and flooded the cave systems. Caves with ceilings higher than sea level were only partially flooded and creating air space. Some of these cave ceilings became too thin and collapsed, creating a sinkhole and leaving a natural entrance to the underground river system.

Cenotes today

Since the 1980s, hundreds of these cenotes have been explored and mapped by cave divers: Today, exploration and penetration still continues. In 2023, nearly 1680km have been discovered.

The three longest underwater cave systems in the world are located in the Riviera Maya:

  1. Sac Actun 376km (228 cenotes)
  2. Ox Bel Ha 339km (152 cenotes)
  3. K’oox Baal 103 km (57 cenotes)

List of Long Underwater Caves in Quintana Roo Mexico

Despite the large number of cenotes, only a few offer large enough cavern areas for recreational divers. A cavern is defined as the area of a cave within the natural daylight zone and no more than 60 m (200 ft) from the surface.

M-DIVING focuses on these cenotes to give you one of your best underwater memories.