The Pit

Sunlight entering the narrow opening forms long beams that reach far down into the mostly roofed-over chamber. The halocline lies in the mid-teens of metres, and below it a milky hydrogen sulphide layer covers the rocky bottom with tree branches sticking out of it. Pleistocene bones marked by the national anthropology institute INAH rest at about 30 m at the back of the chamber, and two human skeletons over 10,000 years old were found in the cenote. Dive centres require Advanced Open Water certification, and going beyond the recreational limit needs technical training. Steep stairs with a pulley for equipment lead down to the water.