Sidrón Cave in Spain

The Sidrón Cave (Spanish: Cueva del Sidrón) is a non-carboniferous limestone karst cave system located in the Piloña municipality of Asturias, north-western Spain, where Paleolithic rock art and the fossils of more than a dozen Neanderthals were found. The total length of this huge complex is approximately 3,700 m (12,100 ft), which contains a central hall of 200 m (660 ft) length and the Neanderthal fossil site, called the Ossuary Gallery which is 28 m (92 ft) long and 12 m (39 ft) wide. Declared "Partial Natural Reserve" in 1995 the site serves as a retreat for five species of bats and is the place of discovery of two species of Coleoptera (beetles).^[2]

• http://en.wikipedia.org/wiki/Sidrón Cave
• Page 202 - Tattersall, I., 2015, The Strange Case of the Rickety Cossack and other Cautinary Tales from Human Evolution: Palgrae Macmillan, 244p.