Cenotes are a characteristic of Mexico and Central America and are especially very common in Yucatan Peninsula where we can find more than 3000 with only 1400 studied and registered. The term is based on the mayan word "dzonot" or "ts'onot" which means "sacred well". And in fact, cenotes were very important for the ancient Mayans.
They were the only way to reach fresh and ground water in this karst plain of Yucatan, completely waterless. They were sacred places, also used for sacrificial offerings.
These natural sinkholes filled of water result from the collapse of limestone bedrock that exposes groundwater underneath. We used to distinguish four types of cenotes : open air wells, underground rivers, underground and dry caves. Some of them are accessible for snorkeling and cave diving.
Dos Ojos (north of Tulum, Quintana Roo) is one of them, among the most popular and the longest underwater cave systems in the world since its discovery in the late 1980s. His extent represents around 51 miles with 28 known sinkhole entrances. It means "Two Eyes" because of its two cenotes appearing like two large eyes into the underground. Its water is exceptionally clear and pure as a result of rainwater filtered through limestone. It is possible to traverse underwater into another adjacent cenote called the "Bat Cave", which is also used for snorkeling.
Gran Cenote (west Tulum, on the highway to Coba) is one of the most popular in the Riviera Maya too. His name does say it all! It is a large beautiful garden cenote with easily accesible caves for snorkeling and diving. Outside, a shallow snorkeling area with soft sand beach, where we can observe with a simple mask impressive stalagmites, stalactites and columns and enjoy the natural open hole and the jungle above. Inside, underwater wonderland where certified cave divers can explore darkness and an incredible decorated cave.