Pozu la Llerona (β10)
β10 is a bright spacious cave. It was first explored in 1985, when it reached a depth of about 300 m. This first part of the cave is made up of deep, roomy shafts, El Autobus and Pozo Peperonatta. A pitch ramp series, El Tocahuevos, was explored in 1986 leading to the final 62 m pitch and then to the final, diminishing Meandro de los Naciones. A further extension by way of a shaft paralleling the final 62 m pitch was added in 1991.