Descend into a whole other world at Cueva-ermita de San Tirso y San Bernabé. There's something fascinating to see at almost every turn in this underground landscape.
Once you've ticked this natural underground attraction in Merindad de Sotoscueva off your to-do list, why not make tracks to Ojo Guareña Natural Monument? It's close to Cueva-ermita de San Tirso y San Bernabé and is one of this area's top sights.