The longest underground river in the world in Mexico

While the Nile and the Amazon are some of the longest rivers in the world, there are rivers below the earth’s surface that are mighty and vital to humanity, supplying up to 50% of drinking water. What is the largest underground river in the world?

The longest underground river in the world and the largest cave system in the world is in Mexico.

The Sac Actun system measures 347.7 km, of which the underground river measures 259 km and has a depth of 101.2 meters. This system has 111 entrances to cenotes, which are characteristic of the Riviera Maya and one of its main tourist attractions.

In 2007, a group of divers discovered what would be the river longest subway in the world in the Riviera Maya.

In 2018, they discovered a connection between the Dos Ojos System, and the Sac Actun System, which became the longest known underwater cave system in the world.

These underground waters keep a great history, since the discovery of archaeological pieces that indicate life before the arrival of explorers, extinct animals and the Mayan culture have been documented.

Why is groundwater so important?

Groundwater is said to make up 99% of Earth’s liquid freshwater and is so vital to the functioning of the water cycle.

Proof of its existence are the rivers, lakes and wetlands that are filled with groundwater when they dry up and are carried away when there is excess on the surface. Groundwater is important for that reason.

In fact, 50% of the human population depends on groundwater to survive.

Visiting the cenotes of San Actun in Mexico

Cenotes in Tulum
Photo by Mauricio Borja from Pexels

The Sac Actun System has more than 220 cenotes, which are very deep water wells, fed by the filtration of rain and underground rivers.

The cenotes of San Actun are one of the most paradisiacal places you can visit, you can snorkel or dive in the impressive cave.

To get there, you have to travel to Tulum, Quintana Roo, Mexico. As it is a very touristy place, you can look for cheap accommodation in Tulum or nearby places, and look for offers that often occur in low season.

Another option is to look for accommodation in Playa del Carmen, which is 60 kilometers from Tulum, which takes about an hour.

Visiting the cenotes of San Actun and the Riviera Maya can be an incredible experience to explore our curious planet.