Charco del Cieno is a protected Site of Scientific Interest located in Valle Gran Rey, on the west coast of La Gomera. It's a small volcanic cove where the sea has formed a natural pool with calm waters, surrounded by dark basalt rocks and black sand. Its scientific value lies in its volcanic geology and its role as a refuge for marine species native to these coasts.

To get here you walk along a short path of black sand from the end of Calle El Tarajal, following a route that runs close to the sea. The area is quiet and maintains a natural, secluded character. Nearby there's also a small beach with dark sand, equally peaceful and uncrowded.

The setting is open and without shade, offering views of the ocean and the cliffs along the southern coast of the island. It's a spot chosen by those looking for quiet corners to enjoy the sea in a volcanic, undeveloped environment.