The Yucatán peninsula is well known for its  cenotes, which are natural freshwater pools or sinkholes with underwater caves and caverns that make a great place to swim, snorkel, or scuba dive. The word cenote is derived from the Mayan word D´zonot.

One of the most beautiful is the Gran Cenote, just 4 km. on the road to Cobá. Its clear water allows swimmers and divers to see the underwater cave formations and the small fish that live there. Cenote Calavera is located about one kilometer before the Gran Cenote, down small, marked path into the jungle (you will see a sign along the highway). Its three holes form the skull shape which gave the cenote its name. This is a beautiful place to jump into the water from above.

Farther up on the highway to Cancun and Playa del Carmen is Cenote Dos Ojos, whose two holes make an excellent place to swim or dive. Cenote Cristal and Cenote Escondido are both located south of Tulum, on the road to Carrillo Puerto and Chetumal, just five minutes from Tulum pueblo. Admission prices include both cenotes.

All of the cenotes of the area are connected by a vast system of underground rivers, which are being explored by the region´s best scuba divers.

How were Cenotes formed?

During the last ice age (approximately 1.5 million years ago), the appearance of the Yucatan peninsula completely changed. The ice caps at the poles grew, while the sea level sank about 100 meters. At this time, the rain water carved holes into the limestone ground, thus creating the space for the evolution of stalactites and stalagmites. (Stalactites hang down from the ceiling of caves, and stalagmites rise up from the ground.) As the ice began to melt again, the sea level began to rise, and the caves were flooded with water once again.

In some places, the underground water streams had washed away the soil, so the ground fell in. The Yucatan peninsula´s world famous cenotes (often referred to as sinkholes or waterholes) evolved. The water which fills the caves today is partly intruding saltwater from the sea, but mainly fresh rainwater. Due to their different density and weight, saltwater and fresh water do not mix. The fresh water "floats" on the saltwater, causing an oily appearance. This is called the "halocline," and is not an impurity; it is a natural effect of the mixture of the two water systems.