Scuba divers exploring Cenote Angelitas underwater river in Mexico. Scuba divers exploring Cenote Angelitas underwater river in Mexico.

The Underwater River: An Epic Place in Mexico’s Abyss Where Fresh and Saltwater Meet!

Are you bored of hiking the trails and camping? And, now looking for some unique adventure? I have a great option for you.

Imagine yourself descending at about 60 feet when you look at the strange, spooky bottom with a few bare tree branches sticking out ghostly. Once the haze becomes clear, you see the surreal expanse of clouds when a creepy feeling takes over you as your brain gets amplified by the effects of nitrogen. Descending deep into the cloud, your light gets engulfed in darkness, and you might bump into the branches. Isn’t this enough to give you goosebumps?

Yes, I’m talking about the black abyss with clear waters that your light cannot illuminate- The Underwater river in Mexico’s Abyss. Believe me, that’s a diving adventure that grips your senses for eternity! Just peeping into the water’s surface gives you a glimpse of the deep blue waters below. So, before you dive into the river, get ready to immerse yourself in this article. Here, I’ll tell you more interesting details about this underwater river.

Let’s Explore the Uncommon Underwater River

The sunken river is located at the heart of the Mayan Jungles outside Tulum in Mexico. Amidst the dense thicket lies a 200-foot sinkhole that is as deep as it appears wide, locally known as a Cenote takes you to the spooky river that flows in the abyss. Only a handful of people have seen the stunning and eerie river. It is called Cenote Angelita, which means “little angel.”

Before we dive deeper, let me clarify a few things for you.

A Cenote– the pool that plunges to Angelita is a deep sinkhole formed from collapsing limestone bedrock. This collapse surfaces all the groundwater or accumulated rainwater below the ground. Remember the thirsty crow story? It’s the same principle here. As a result, the surface water you see at the top of the Cenote is always crystal clear.

These Cenotes are several feet deep and have colossal lengths of up to 10 meters in diameter.

They also possess massive underground cave systems stretching over several kilometers. So, this Cenote was used by the Mayans as a water source that has spiritual qualities. And the best part is that Cenotes possess an enormous wealth of archaeological finds. Several priceless Mayan artifacts have been excavated on the Cenote surface that is believed to have been thrown into it.

Cenote Angelita: "Underwater River"

Here, I would like to warn you as It’s a bit challenging to get to the caves and requires significant experience in diving. The waters appear clear for the first 20 meters and increase to become murky as you go deeper. However, the entire dive into the cave goes up to 55 meters underground.

There Is an Interesting History Behind the Underwater Rivers

It’s now time to explore the history beneath the waves and swim backward to the once upon a time of the Cenote…

The Cenote Angelita is one among the 6000 Cenotes found in the Riviera Maya in the Yucatan Peninsula of Mexico. Its evolution dates back thousands of years ago with the collapse of limestone bedrock that trapped both salt and freshwater inside its fissure. But the unique feature of this particular Cenote is that it harbors a halocline that appears as the underground river itself.

Actually, it’s nothing but hydrogen sulfate that is formed exactly where the freshwater and saltwater meet. This is a beautiful phenomenon that gives the smoky interface between the two. So, if you ask me whether Angelita is an underground river, the answer is NO!

The halocline, or the hydrogen sulfate layer, slithers in a river-like movement between the fresh and saltwater that is mistaken for the river for many divers. And these withhold a mass of debris like sunken leaves and tree branches from sinking further down the salt water.

1. Discovery of Angelita

This region was well-known to the Mayans or the Mesoamerican Indians living in southern Mexico. They considered the Cenote sacred apart from being a primary water source. Also, they believed that it was the gateway to the underworld or Xibalba, where the Mayan deity Chaac who ruled over rain, lightning, and thunder, resided. Hence, they used the Cenote for ritualistic ceremonies or even during human sacrifices.

Most of the objects used for these ceremonies were thrown into the Cenote, which has made it a place of uttermost archaeological importance. The sunken objects like artifacts and relics remain in a good state, allowing archaeologists to study the Mayan Civilization.

2. Popularity in the Civilized World

Anatoly Beloshchin, a Russian undersea photographer, was the first to find this particular Cenote while taking a dip there. He has hiked over the Antarctic and swum with sharks and whales. But there is none more exciting to the pictures he captured while venturing into the subterranean of Angelita. It all relied on his curiosity to see what lies below the freshwater that publicized the underground river to the world.

All his photographs might look like an optical illusion of the so-called underground river, but everything is actually true!

You might get the same feel as seeing a river on land with soil, trees, leaves, and banks. But till now, the river below Angelita remains nameless. Though the swamp gas is nicknamed hydrogen sulfide, it does not entirely comprise that chemical. Even brine and methane are deposited in the gas. This makes the river highly toxic, unfit for fishing or penetrating through a submarine. That’s why the regular flora and fauna cannot survive in this river.

But records show the presence of a species of mussels thriving on the ‘banks’ of the underground river. These unique creatures can flourish in methane and other toxic environments without sunlight! Their source of energy for survival is a type of bacteria that converts chemicals and methane into energy.

Now Let’s Find Out How Underwater Rivers Work

Water is the prime part of life to thrive on Earth. You might have come across the fact that 70% of the planet comprises water. While many people like you know just the existence of rivers, lakes, and oceans, few know the existence of underground lakes and rivers. Most of them are hidden from the outside world, but if you chance upon it, you will be astonished to know the fascinating science of hydrology that works in them.

These are not just water bodies existing underground. Rather they are complex systems that require a profound knowledge of geology, physics, and chemistry to understand their existence fully. Scientists have discovered a few secrets about the features of these sub-surface rivers through research and exploration.

But to make you familiar with what’s happening below your feet, here’s a diluted version of the science behind the lakes and rivers running below the water. I’ll magnify the physical properties that enable water to flow in such a manner creating underground channels and even an underwater waterfall!

1. Thermohaline Circulation- The Process that Creates Rivers and Lakes Underwater

Thermohaline Circulation

It’s fascinating to know that this process results in the formation of rivers and lakes under the water. This process occurs when water of various densities and temperatures circulates throughout the ocean. And the place where they meet creates the river-like flow that is otherwise called the deep-water current.

You can find this process taking place in more profound parts of lakes where a layer of cold-water plunges and mixes into the warm water. As a result of this mixing, a current is generated and starts flowing through the lake bottom, creating the rivers underwater.

These rivers and lakes are a prime feature that sustains marine life’s health and creates distinct landscapes for divers to explore!

2. The Process Occurs When Cold-Dense Water Plunges into the Bottom of the Ocean or Lake and Generates a Current

Cenote Angelita - Underwater River, Mexico 🇲🇽

Now, the process of sinking the cold, dense water to the lake or ocean bottom and generating a current is known as thermohaline circulation. I hope you are clear about that.

This is the prime process that creates underground lakes and rivers. This circulation is affected by the salinity and temperature of the water masses. For instance, the cold, salty water is heavier than the warm freshwater. So, as the dense salt water plunges deep into the bottom, it can carve out channels in the sediment beneath.

Diving into an Underwater River Could be Risky

Most underwater rivers might be dangerous, especially if it’s filled with debris. There are chances that divers can get entangled, causing injuries and even death! If it’s polluted, you can get seriously ill.

In the case of Angelita, the Cenote in Mexico, the colorless, toxic hydrogen sulfide gas, assumed as the ‘river’ flowing underwater, is highly toxic to humans. The layer is over 10 feet, making only experienced divers make it through the cloud. Just one gulp of the rotten egg-smelling toxic gas into your system can kill you in minutes.

Hence most visitors are allowed to dive over the cloudy surface!

Most of the divers who visited the river flowing underwater in Mexico state that it looks and functions like the regular river you find everywhere. It has a shore tainted by leaves, branches, and muck punctuated by a turbid stream. They call it the world’s most surreal place and a diver’s paradise!

Still can’t shroud your head about the notion of an underwater river? Then check the video below. You’ll (nearly) feel like you were there!


Last Updated on May 9, 2024 by Pragya


  1. Enjoyed your article, and was lucky to find it in the first place! So many fascinating and intriguing details of the underwater river. It is like a whole different world, especially when there is hydrogen sulfide which creates the mist. So eerie!

  2. A very good and informative article about the underwater river. The underwater world is full of mysteries and the underwater river is surely one of them. Our life is too short to solve these mysteries.

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