For the Mayan civilization, the cenotes were the birthplace of life, windows to the underworld, and containers of sacred waters. And in reality, being the only point of access to the underground aquifer, the cenotes of the Yucatan Peninsula give life to animals, plants, and humans.

In the absence of rivers and lakes, life on the peninsula is sustained by the underground aquifer that has been formed by the infiltration of rainwater through the porous and fractured soil that characterizes the region. But the porosity that gives origin to the aquifer also makes it susceptible to contamination, because not only rain but also pollutants can infiltrate to reach the water contained in the subsoil. Once there, the contaminants can be stored or distributed and spread the contamination problem.

The underground aquifer is the main source of freshwater for human settlements on the peninsula, including the cities of Merida, Cancun, and Playa del Carmen. As the only bodies of water in the north of the peninsula, the cenotes are vital for biological diversity. They provide water and are a habitat for insects, reptiles, mammals, birds, fish, and plants.

When it falls, rainwater becomes slightly acidic as it absorbs carbon dioxide from the atmosphere (CO2). When it reaches the ground, the acidic water dissolves the stone that forms the subsoil of the peninsula and makes it more porous. Rainwater continues to dissolve the limestone, forming cracks and fractures that widen to form caves. Over time, the cave ceiling can collapse, exposing the water table. At that point, a cenote has formed.

As it filters through the subsoil and reaches an air cavity, the CO2 dissolved in the water becomes a gas again and the water loses its ability to dissolve minerals. This causes the minerals to be deposited forming stalactites, stalagmites, and columns. The process of dissolving limestone has been going on in the Yucatan for about 60-70 million years. This is the reason for the region's characteristic landscape. This landscape is called the karstic landscape.

Cenotes and humans

Cenotes are charged with historical significance and have been revered by Mayan communities. In the peninsula, the pre-Hispanic Mayan population depended almost entirely on water from underground aquifers, which they accessed thanks to the cenotes, caves-cenote, and wells. They also collected rainwater in chultunes, deposits similar to cisterns that were built in the limestone.

In the 16th century, the priority of colonial policy was to establish human populations where water supply was guaranteed. For this reason, the communities of the time were associated with one or more cenotes. In the 19th century, at the height of the henequen industry, water from the underground aquifer was used to supply the haciendas. Today, cenotes have become a tourist attraction. Although in some communities they are still the main source of freshwater and maintain their spiritual importance.


According to estimates, in the Mexican state of Yucatan one of the three states that make up the peninsula along with Quintana Roo and Campeche, there are between 7 thousand and 8 thousand of these formations, in which trash of all kinds has been found, which has caused that your freshwater registers high levels of contamination.

Porosity and cracks in the subsoil make the underground aquifer very susceptible to contamination. For sewage, pesticides, fertilizers, motor oils, and other liquids can percolate into the groundwater. In the peninsula there is no public drainage system, most of the wastewater ends up in sinks that go directly to the aquifer or to septic tanks that do not provide sufficient treatment. By 2014, only 2.4 percent of wastewater from Yucatan homes was treated.

In the Yucatan Peninsula, the cenotes are used by the inhabitants as a tourist attraction and hundreds of families in the police stations and municipalities of Yucatan subsist thanks to them.

More than 8 tons of waste have been removed in recent months from the cenotes, which encouraged the population and tourists and visitors, national and foreign, to keep the cenotes clean. Although there are hundreds of cenotes that have been contaminated, there are also others that have preserved their beauty and are preferred by tourists for their fresh and crystal clear waters.

Swimming in the Mayan cenote.
Swimming in the Mayan underworld spell. Photo: Flickr

Cenotes in Yucatan, a natural treasure

There are more than 6,000 cenotes in the Mexican peninsula of Yucatan, mere geographical features that were given a supernatural character. As soon as the tip of your foot crosses the sheet of water, you enter the kingdom of Xibalbá, the Mayan underworld.

Not to be suggested by the environment and the stories read and heard in the previous days is almost impossible when it comes to swimming in a cenote. The mind tries to remember that it is a mere geographical accident, the work of time, and the wear and tear of the rock. Underground rivers have been exposed when a part of the vault of the grotto has collapsed leaving an eye of water visible. But the vision is more powerful than the coldness of the data.

In general, the waters of a cenote are accessed by going down the stairs in a gallery in which light filters through the ghostly lianas that hang along the edges of the hole. The rays of the sun, in the central hours of the day, send mystical beams that highlight the jade of the liquid. When getting into the water, one remembers that underneath there is a vertical tube up to a hundred meters deep that connects with the other cenotes of Yucatan.

Swimming in the cenotes is a joyful experience in a scorching climate.

The Mayas built their towns and cities - and built their most magnificent palaces and pyramids - always close to cenotes, as they were the well with which they fed the population with water. And, perhaps because of its oneiric aspect, they gave it a supernatural character. Underwater is not exactly hell, but the underworld of disease and death is ruled by Xibalbá.

In some cenotes, the ancient Maya made human sacrifices. In the background, archaeologists have found skeletons of children, generally under the age of 11, who had been skinned and subsequently burned. In some of the caverns, there are even marked petroglyphs on the walls below the water level.

And, despite all this cultural background, the cenotes are one of the quotes highlighted in red by travelers traveling through the far south of Mexico. It is a joyful experience in a scorching climate. Entering cold water and transparency seems impossible. The younger the cenote, the purer the water. As the centuries go by, the mineral deposits turn the water into a cloudy emerald color.

There are still unconditioned cenotes, wild in the thickness of the Yucatec jungle

There are hundreds of cenotes in Yucatan, many of them open to the experience of the public. Most propose safety measures, such as forcing swimmers to wear life jackets and equipping the swimming area with ropes to hold on to in case the current drags hard or, simply, so that you don't cross to the points where the depth is -literal- abysmal.

Due to their relationship with the classic Mayan world, some of the most popular cenotes are attached to the most visited archaeological sites in Mexico, such as Chichen Itzá. In the ruins, themselves is the Sacred Cenote that the city's builders used for their water supply and rituals. But only three kilometers away, tourists enjoy the Ik-Kil cave, a place devised by a Hollywood scriptwriter.

There are even cenotes in the urban center of some cities, as in the case of the Zaci of Valladolid; and others still unconditioned, wild in the thickness of the Yucatan jungle. But dozens of them are ready to receive visitors, such as the Gran Cenote de Tulum, where you can visit part of the caverns diving, or the recently opened X-Batun and Dzonbakal. Even those who have a Mayan museum inside, such as Dzibilchaltún. In any case, an experience that can only be lived in Yucatan.

How the underground rivers were formed

The cenotes and subterranean rivers formed thanks to the calcareous soil of the region, which absorbs rainwater by storing it in the subsoil and creates the flooded caves that have attracted thousands of tourists every year. The origin of the cenotes and underground rivers is related to a meteorite that fell on the Earth, 65 million years ago. It is believed the impact was so strong that it left a crater 200 kilometers in diameter and caused the destruction of 75 percent of the life of the planet, including the disappearance of dinosaurs.

After the geological alterations produced by the meteorite, a ring of underground caves joined together, known as the "Ring of Cenotes", was formed, which was the precursor of the current underground rivers and cenotes of Yucatan. This region also has the longest underground river in Mexico, called Ox Bel Ha, with 182 thousand meters in length.

New species discovered

A new species of the feline was found in the Cenote Pit, north of Tulum. According to the research of the Institute of the Prehistory of America, it could be an endemic species of the Peninsula that became extinct in the Ice Age.

The animal in question was named Panthera Balamoides about the word "Balam", the name by which the Maya identified the jaguar. It is said that it was a type of giant cat that lived about 10,000 years ago and was a native of the region (what at that time was considered the Yucatan Peninsula).

The finding, made by Sarah R. Stinnesbeck; Wolfgang Stinnesbeck; Eberhard Frey; Jerónimo Avilés Olguín; Carmen Rojas Sandoval; Adriana Velázquez Morlet and Arturo H. González, was annexed to a catalog of 30 species discovered in the region and adds to the past discoveries of a sloth and a peccary, both extinct, like the Balamoides, more than 10,000 years ago.

Sources: Agencia Informativa Conacyt