Cave of el Puerto Nature · Calasparra, Noroeste, Murcia Natural cavity located in the Sierra del Puerto-Cabeza del Asno, on the slope of the monte de Chatres, nine kilometres from Calasparra, in the northwest of the Region of Murcia. With about 4.4 kilometres of surveyed galleries and a drop of 114 metres, it is the region's most extensive horizontal cave; the stretch enabled for visits, more than 700 metres long with a drop of about 50 metres, shows stalactites, stalagmites, columns and other formations such as jellyfish, organs or eccentrics. It formed in limestone and dolomitic materials of the Upper Cretaceous, and the valley's inhabitants had known it for at least five generations because of its connection to the aquifer and the manantial del Borbotón. Photo: Anidae (CC BY 4.0) What to see and do in Calasparra