Nestled deep within the Sierra Gorda Biosphere Reserve, El Sótano de Barro is one of Mexico’s most awe-inspiring geological formations. Located in the municipality of Arroyo Seco, about 35 km northwest of Jalpan de Serra, this colossal open-air sinkhole is the second largest of its kind in the world.
Formed approximately 1.5 million years ago by the collapse of limestone bedrock, El Sótano de Barro resembles an inverted cone with staggering dimensions: a depth of 455 meters, a vertical drop of 410 meters, and a mouth that stretches 420 meters across at its widest point. Its volume is estimated at 15 million cubic meters, making it a true giant among natural cavities.
Beyond its geological significance, the site is a sanctuary for biodiversity. Most notably, it hosts the largest known population of the endangered green macaw (Ara militaris) in Mexico. These vibrant birds nest in the cavern’s vertical walls and perform a spectacular daily ritual—emerging in flocks at dawn to forage, then returning at dusk. Observing this phenomenon is a highlight for both ecotourists and birdwatchers.
The surrounding terrain is rich with mesophilic forest vegetation and is home to species such as pumas and collared peccaries. Due to its ecological importance, access is limited and regulated to protect the habitat.
Visitors can hike to the rim for panoramic views and camp nearby to witness the macaws’ flight. However, reaching the site requires navigating rugged terrain, making it ideal for adventurous travelers seeking a raw and unforgettable experience.
El Sótano de Barro is not just a geological wonder—it’s a living, breathing testament to Mexico’s natural heritage.
Source: El Souvenir
