A unique lake that combines science, legend and nature in Costa Quebrada

Inside the UNESCO Global Geopark Costa Quebrada, away from the roar of the Cantabrian Sea, lies a setting of silent beauty and ancient legends: Pozo Tremeo. This small natural lake, unique on the coast of Cantabria, concentrates in just a few meters the purest essence of the region: untouched nature, popular mysticism and a serenity that seems to suspend time between green reflections and the murmurs of water. There are places that are discovered with the eyes and others that are felt beneath the feet. Pozo Tremeo belongs to the latter. Located in Rumoroso, in the municipality of Polanco, this small lake formed over a karstic terrain, when the limestone bedrock collapsed and trapped water in a natural hollow. This is how this unique enclave was born, surrounded by lush vegetation and enveloped in a silence that breathes life. Since 2016, Pozo Tremeo has been protected as a Natural Area of Special Interest, not only for its geological rarity — it is the only natural lake on this coastal strip — but also for the ecosystem it harbors. More than 200 plant species and around 170 animal species coexist in its surroundings, from birds and bats to small reptiles that glide through the shadows of the forest. The lake gives rise to Arroyo Salín, which demonstrates that it is part of a living and connected system.

Pozo Tremeo is located on the outskirts of the town of Rumoroso, which belongs to the municipality of Polanco © Cantabria Tourism

Its name comes from the Latin verb tremere, “to tremble,” and simply approaching the shore is enough to understand that. The ground seems to move, as if water were breathing beneath it. That trembling inspired legends for centuries: stories of lovers who never parted, wishes that come true by touching the water and even rumors about tunnels connecting it to the sea. Myths that still linger in the mist of cold mornings. The visit to Pozo Tremeo is simple and accessible. The route is perfect for families and nature enthusiasts. Along the way, informational panels explain its formation and biodiversity, and some guided routes, even dramatized routes, turn the experience into a sensory adventure. Here, there is no rush or affectation. Only the sound of water, the song of birds and the echo of the wind.

Location

The town of Rumoroso is situated in the municipality of Polanco, in the northern part of the region of Cantabria. It is located approximately 26 km from the autonomous community’s capital, Santander. It can be accessed by car via the A–8 motorway and the CA–131 road. It is also close to the Requejada stop (commuter rail) and Santander Airport, about 16 km away.