El Soplao is a cave located in the municipalities of Rionansa, Valdáliga and Herrerías in Cantabria, Spain. It is considered unique for the quality and quantity of geological formations in its 17 miles length, 6 of which are open to the public. In it are formations such as helíctites and curtains. Its formation dates back to the Mesozoic, in particular the Cretaceous period 240 million years ago.
The entrance is at 540 metres in the Sierra Soplao Arnero.
Wikipedia https://en.wikipedia.org/wiki/Cave_of_El_Soplao
Official Website https://www.elsoplao.es/
Email elsoplao@elsoplao.com
Phone +34 902 820 282
Coordinates 43°17'47.34" N -4°24'36.456" E