El Soplao cave, considered as one of the great treasures of world geology, once a mine, but in 1975 when that was closed speleological exploration began to reveal a unique and spectacular crystallographic content. Situated 62 kms from Santander in beautiful natural surroundings , this is a visit not to be missed. Apart from stalactites and stalagmites. the helictites formations are truly exceptional. The Soplao caves are reached by a mining train and there is a guided tour of 1.500 metres lasting for an hour. For the more adventurous there are longer tours of two and a half hours covering 6 kms. Resevations must be made by telephone. For the shorter visit children under six are not allowed and for the longer excursions the minimum age is sixteen. Call centre: 902 820282.