The caves of Arguedas and Valtierra emerged towards the end of the 19th century as places that could serve as homes for local people who could not afford to buy somewhere to live. The lay of the land meant that these caves could be dug in the rock, along the front of the rock face to make use of natural light, as only the better-off had electricity supplies in their homes. There were no corridors and you passed directly from one room to another. Many of the homes had a grain store and a yard, as the majority of their owners were small farmers. These natural, bioclimatic shelters remain at a steady temperature between 18º and 22ºC all year round. Nowadays some of these caves have been converted into tourist apartments.