Fuentes Termales de Tiermas

Tiermas is a medieval village in the province of Zaragoza in Aragon, whose bicarbonate thermal springs rise beside the Yesa reservoir, where the village — submerged in the 1950s during dam construction — periodically re-emerges during extreme droughts, with the original streets, church foundations, and thermal spring sites rising ghostly from the receding water. The thermal springs of Tiermas were developed by the Romans and used throughout the medieval period by pilgrims on the Camino Aragonés route to Santiago de Compostela, making them one of the oldest documented thermal sites on any pilgrim route in Spain. During rare low-water events, the re-emergence of the drowned village above the reservoir with the original thermal springs still flowing among ancient foundations creates one of the most singular and hauntingly beautiful natural spectacles in the entire Pyrenean region.