Los Rápidos de Bacalar is a waterway that’s the color of a pale, aquamarine gem in some places, and a deep indigo blue in others. It extends 35 miles across a lesser known corner of the Yucatán Peninsula in Quintana Roo, Mexico, just north of the border with Belize.

Dotted with small islets, the waterway connects the southern and northern parts of the Bacalar Lagoon, a body of water full of rare microorganisms that harken to the beginning of life on Earth. Also known as the Lagoon of Seven Colors, the Bacalar Lagoon mesmerizes with its variety of hues. It’s also home to living colonies of stromatolites, which thrive in the lagoon’s uniquely alkaline environment and are responsible for its magical array of blues.

Living stromatolite colonies look similar to coral, but are extremely rare, existing in just a handful of places in the world. The stromatolites in Los Rápidos are a relatively new addition to the landscape, dating back to the Holocene era, which began about 12,000 years ago and continues today. But they are remarkably similar to the microbial organisms that were among the first living things on Earth.

The oldest known stromatolite fossils clock in at around 3.7 billion years old, not much younger than our planet itself. They were formed by layers upon layers of cyanobacteria, the same bacteria from which all life on Earth has stemmed and which made the earth’s atmosphere a habitable and pleasant place for life to thrive.

At Bacalar, these bacterial formations aren’t among the oldest on Earth, but they show us what those structures looked like when they first emerged. These living rocks are a treasure. Combine them with a multi-colored lagoon and a relaxing, undeveloped landscape, and a ride down Los Rápidos de Bacalar will be a memory that will stay with you for a very long time.

What to consider

  • You can book a tour or go by yourself. Take a taxi from Bacalar to Los Rápidos and float (or swim) from the river to the lagoon.
  • No credit cards are accepted at Los Rápidos.
  • Bring your own snorkeling gear.
  • Wear reef-safe sunscreen only. Sunscreens that are not labeled as reef safe kill off the microorganisms that make coral and cyanobacteria thrive.