This was an unexpected discovery we made, completely unaware of it at the time, during our trip to Mexico way back in 2015.
Wrapping up our two-week journey, already on our way back toward Cancun, we stopped at the breathtakingly beautiful Bacalar Lagoon (๐๐ฎ๐ด๐๐ป๐ฎ ๐๐ฎ๐ฐ๐ฎ๐น๐ฎ๐ฟ, ๐๐ฎ๐ด๐๐ป๐ฎ ๐ฑ๐ฒ ๐น๐ผ๐ ๐ฆ๐ถ๐ฒ๐๐ฒ), also known as the Lagoon of Seven Colors, where, as they say, the water shimmers in seven different shades, ranging from turquoise to emerald green.
As we stood on the shore, admiring this wonder near a small pier, a young man approached us and offered a three-hour boat tour, showing us a photo album of all the places we would visit. He also mentioned that we would have a chance to swim in the lake.
At first, we drifted for quite a while through a system of interconnected lakes, where the depth of the lakebed varied dramatically. Right before our eyes, the water shifted colors multiple timesโit was fascinating and mesmerizing. Shades ranged from a milky emerald to deep sapphire blue.
Along the way, our skipper pointed out a system of underwater cenotes, which were impossible to miss: the milky emerald hue of the waterโdue to the limestone bed belowโsuddenly gave way to an abyss of dark blue. This was a karst sinkhole with a staggering depth ofโwait for itโ90 meters! The next cenote, as our boatman told us, was “only” 70 meters deep.
And then, we drifted into a unique, textured bay, and the boatman, using hand gestures and simple words, tried to explain to us that these were “LIVING STONES.”
And that was the moment we realizedโwe had made complete fools of ourselves! The boatman kept pointing at some strange rock formations in the water, these odd pillar-like “blobs,” and saying some unfamiliar word (which, as it turned out, was “estromatolitos”). We could tell these rocks were something special, that they had a story, but with our limited Spanish, we had no idea what it was. So, we took a few pictures just in case and moved on.
Stromatolites were clearly visible. They resemble cauliflowerโlarge beige cushions growing upwards from the limestone bed of the lagoon.
Eventually, our boatman brought us to a narrow channel and suggested we go for a swim. But not just any swimโhe proposed we float downstream along a fast-moving current (this place is called “Rapidos de la laguna”). He dropped us off in the water and took off in the boat, heading downriver to meet us about a kilometer ahead.
The channel Rapidos de la laguna translates to “the rapids.” It is lined with stromatolites.
It was pure bliss! We had snorkel masks and tubes, drifting effortlessly with the current, watching schools of tiny fish darting around us, exploring little inlets along the way, and even diving under bizarre rock formations that created underwater caves and arches. These were the very same “Living Stones.” The current carried us forward, we tumbled and spun in the flow, playing however we wanted, simply enjoying the ride. I highly, highly recommend it!
Stromatolites are sedimentary structures, similar to coral formations, created by the activity of ancient single-celled microorganismsโcyanobacteria (blue-green algae)โthat have existed for more than 3.5 billion years, dating back to the Precambrian era. These bacteria played a crucial role in forming Earth’s atmosphere as we know it today.
The name “stromatolite” comes from the Greek words stroma (meaning “layer” or “mattress”) and lithos (meaning “stone”), literally translating to “layered stone.” They are made up of colonies of microorganisms that secrete a special sticky substance. This slimy layer attracts and traps sediment particles floating in the water. Over time, the algae fibers move upwards, creating a new organic layer. Eventually, these layers decompose under the influence of specialized bacteria and become interspersed with sedimentary deposits. However, the top layer of the structure remains aliveโa delicate mat of algae fibers, often over a meter high, which feels like a sponge to the touch.
Living stromatolites are a rare relic of Earth’s historyโthey exist in only five locations worldwide.
Once we got home, I decided to search online to find out what these “Living Stones” really were. At the time, there was barely any information in Russian. What little I found claimed they werenโt actually stones at all but rather a type of enormous freshwater coral that continuously grows and is hundreds of thousands of years old.
But doubts remainedโwhat kind of corals were these? Finally, after searching through Spanish and then English-language sites, I found out that these “living stones” were actually stromatolites. And in the narrow strait of the lagoon called “Los Rapidos” lies the largest colony of these freshwater microbialites on Earth. The stromatolite reef in Bacalar Lagoon stretches for 10 kilometers, with some formations reaching several meters in height. The stromatolites in Bacalar are about 3.5 billion years old!
Today, there is plenty of information online about the incredible “living stones” in Bacalar Lagoon. They are now treated with much more careโtouching them is prohibited, boats are not allowed to pass through, and they are protected by the government as a natural heritage site.
Fossilized stromatolites can be found in many places around the world and are even used as an expensive building material. But living colonies like these have survived in only a handful of locations on the planet. And Bacalar Lagoon is home to the largest known colony.
So there we were, swimming among living fossils without even realizing it! And if we had known? We probably would have been overwhelmed with emotions!
Later, my husband told me, “You didnโt prepare well for this trip. Thatโs a fail.” Because aside from the stromatolite surprise, I had overlooked another detail.
At the end of our boat trip, the captain dropped us off at what he called a “natural beach,” at the mouth of the Pirates’ Channel (En el canal de los piratas), near the ruins of an old restaurantโformerly a barge. The banks of the channel were lined with mangroves, and we learned that white mangrove trees grow here.
I only found out about the “Pirates’ Channel” later when I checked Google Maps. I also read that people come here specifically for spa treatments, as the sand in this area is rich in minerals, providing an incredible full-body exfoliation. This is a well-known spot for natural spa treatments. Well, who would have thought?
But now, you know everything! If you ever visit Mexico, make sure to go to Bacalar Lagoon (just 340 km from Cancun). You might even want to stay for a few days to fully enjoy the lagoonโs unique beauty, the spa treatments, and swimming among the stromatolites and cenotes. I already envy you!
