The CA281 south from Puentenansa follows the Río Nansa upstream. Along the way, a 2km detour east leads to the attractive hamlet of Tudanca, dominated by this brilliantly white 18th-century rural mansion. The house, filled with centuries-old furniture, was built by an indiano (returned emigrant made rich in Spain’s Latin American colonies, in this case Peru). It also contains the 18,000-volume library of writer José María de Cossío, to whom it belonged in the 20th century. Guided visits last 45 minutes.