© Shutterstock

Gateways to the underworld -

In Maya culture, cenotes were more than just bodies of water. They were considered gateways to the underworld, sacred places connected to the gods and the afterlife.

© Getty Images

Where Chaac called home -

In fact, ancient Maya believed that the rain god Chaac resided in cenotes.

© Getty Images

Spiritual significance -

As such, the spiritual significance of cenotes was reflected in the way the Maya used them in their rituals and ceremonies.

© Getty Images

Practical purpose -

Besides their place in sacred ritual, cenotes played an equally important practical role in Maya culture as vital sources of fresh water.

© Public Domain

Fresh water supply -

Indeed, these groundwater reservoirs were crucial to the survival of Maya communities.

© NL Beeld

Key to survival -

Cenotes supplied not only drinking water, but served as key points for agriculture and wildlife development.

© NL Beeld

Cenotes of the Yucatán Peninsula -

In central America, cenotes are found in Belize and in Mexico, especially throughout the Yucatán Peninsula.

© Getty Images

Ring of cenotes of Chicxulub Crater -

A higher-density circular alignment of cenotes overlies the measured rim of the Chicxulub Crater, the meteorite impact site associated with the mass extinction of the non-avian dinosaurs.

© NL Beeld

Pockmarking the peninsula -

Actually, the Yucatán Peninsula alone has at least 6,000 cenotes, with some estimates putting the figure closer to 10,000.

© Shutterstock

How are cenotes formed? -

Cenotes are formed by a process called speleogenesis. In other words, the limestone bedrock is dissolved by acidified rainwater and seawater until it collapses in upon itself, creating a system of caves and sinkholes.

© Getty Images

Caves and caverns -

Over millennia, some of these limestone sinkholes collapsed to form cenotes while others in the region eroded, forming vast networks of flooded cave systems.

© Getty Images

Largest cave systems in the world -

Mexico has some of the most expansive underwater cave systems on the planet, a vast maze of submerged labyrinths most of which remain unexplored.

© Getty Images

Top cavern and cave diving destination -

The country is one of the top cavern and cave diving destinations in the world, and there are organized efforts to explore and map these underwater systems. Incidentally, cavern diving in this context is the exploration of a cenote while remaining within sight of its entrance.

© Getty Images

Sistema Sac Actun -

In 2018, scuba divers found that two of Mexico's longest submerged cave networks—Sac Actun (164 miles, or 234 km) and Dos Ojos (52 miles, or 83 km)—are actually connected, creating an enormous flooded cave called Sistema Sac Actun that's officially the largest in the world, at over 216 miles (347 km) long.

© Getty Images

Cenote swimming -

Cenote swimming and cavern diving requires no special permit, and these "sacred eyes of water," as the Maya described them, are hugely popular with visitors.

© Shutterstock

A specialist pastime -

However, cenote cave diving requires special equipment and training, with certification for cave diving a mandatory requirement.

© Shutterstock

Only for the experienced -

Both cavern and cave diving necessitate detailed pre-water briefings, and many hours' diving experience.

© Getty Images

Immersing in the beauty of the region -

Taking to the crystalline waters of a cenote is to immerse oneself in the natural beauty of the region. Cenotes are fed by rain water that is filtered slowly through the ground, thus exceptionally clear and translucent.

© Shutterstock

The halocline effect -

Cenotes located near the coast are filled with fresh water on the surface and deeper salt water. In oceanography, the natural line between fresh and salted water is called a halocline.

© Shutterstock

A haven for flora and fauna -

Cenotes are breathtaking and awe-inspiring in their beauty. Besides their aesthetic appeal, these underwater reservoirs harbor an amazing variety of flora and fauna. In this photograph, a shoal of tetra are seen swimming against a backdrop of water lilies.

© Getty Images

Cult of the Cenote -

A rather more macabre aspect of these otherwise sparkling subterranean reservoirs is the Cult of the Cenote.

© Getty Images

Human sacrifices -

According to legendary tradition, the Maya under the auspices of the Mayapan in the Yucatán Peninsula selected people as human sacrifices and threw them into cenotes to appease the rain god Chaac.

© Getty Images

Cenote Sagrado -

Central to this ritual was the Cenote Sagrado ("Sacred Cenote"), located at the Maya archaeological site of Chichen Itza.

© Shutterstock

Edward Herbert Thompson -

We know this because from 1904 to 1910, American-born archaeologist and notorious plunderer Edward Herbert Thompson systematically drained the Cenote Sagrado and recovered artifacts of gold, jade, pottery, and incense, as well as human skeletons.

© Public Domain

A way to the underworld -

Only a select number of cenotes were used in this way, which suggests that Maya religious officiants believed that only certain cenotes led to the underworld.

© Shutterstock

Cenote Xkeken -

One of the most magical of all Mexico's mystical sinkholes is Cenote Xkeken, an underground cave style cenote set in a closed limestone cave. Huge stalactites hang down from its ceiling to lend Xkeken a truly unworldly veneer.

© Shutterstock

Aligned with archeology -

As you'd expect, many cenotes in the Yucatán Peninsula are located near prime Maya archaeological sites, including Dos Ojos (pictured) and cenotes at Dzibilchaltun and those at Choo-Ha, near Coba.

© Getty Images

A fragile ecosystem -

The beauty—and fragility—of Mexico's cenotes is such that UNESCO has placed the Ring of cenotes of Chicxulub Crater, mentioned earlier, on the World Heritage Tentative List. Meanwhile, the Culture of the Cenote is protected by the UNESCO Convention on the Protection of the Underwater Cultural Heritage.

© Shutterstock

Under threat -

And there's now some urgency in protecting all these extraordinary and iconic natural wonders. Since 2023, some of Mexico's sacred eyes of water are increasingly threatened by the spiraling number of pork and poultry farms that pollute the aquifer. Environmental organizations that carried out studies on the water quality alerted Yucatán authorities of the high levels of toxic substances and lack of wastewater treatment plants in the region. 

Sources: (The Yucatan Times) (UNESCO) (National Geographic) (CN Traveler) (ScienceDirect) 

See also: Wonders of the Yucatán Peninsula

© Getty Images