Cenote is the Spanish interpretation of the Mayan word Dzonot

Cenote. The Yucatán Peninsula is covered with a limestone shelf and rain water penetrates the limestone quickly and forms pools and rivers underground.
The water in these underground pockets is crystal clear with a refreshingly cool 25.5 (78F) temperature. There are over 6000 cenotes on the Yucatan Peninsula – the largest collection in the world.
The Chicxulub Crater to the north-west of Merida has the more cenotes than any other area of the Yucatan. The crater was caused by the massive impact of a huge meteor also blamed for the resulting climate change and extinction of the dinosaurs.
The Maya, like many Mesoamerican cultures, believed that caves were sacred places. Cenotes were usually the only source of freshwater and the ancient culture depended on them for domestic and agricultural uses. There are no rivers in the Yucatan except for cenotes.
The Maya believed the cenote was a portal to the underworld. Archeologists have found many offerings in cenotes including, jewelry of gold and jade, as well as animal and human remains. These offerings were offered to the Gods to ensure the water source and fore overall community prosperity.

The local Mayas called them dzonot and the Spanish reinvented the word to Cenote. The Spanish loosely translated this to mean “deep thing.” The dictionary of Mayan hieroglyphics, defines dzonot as “abysmal and deep”.
Inside many cenotes stalactites and stalagmites form into strange shapes from the ceiling and floor of the cave. Many have a hole piercing the earth’s crust so that when the sun shines on the hole, the cave is lit up as if a marquis light in a theatre.
There are four different types of cenotes: Completely underground, Semi-underground, Land level pond type, Open wells.
Cenotes are now entertainment. Cenotes have become a tourist attraction in the Yucatan and you can now visit a plethora of different types. Even at the Mexican amusement Park of Xcaret, a cenote system is used to transport thousands of tourists with lifejackets float down an underground river to a tropical fish feeding pond. Other cenotes have zip line access or have diving tours with instructors who will lead or teach you scuba diving.