Tiermas

Tiermas is an abandoned settlement in the municipality of Sigüés, on the banks of the Aragón river and the Yesa reservoir, in the province of Zaragoza, Aragon, Spain. No one lives here today — what remains are the ruins of houses, traces of a once-famous spa, and open views over the reservoir that reshaped the whole area back in the 1960s.

Why is the village abandoned?

The construction of a dam on the Aragón river and the creation of the Yesa reservoir forced the residents of Tiermas from their homes over fifty years ago. The neighbouring villages of Escó and Ruesta share the same fate. Tiermas itself was not fully submerged, but decades of depopulation and neglect left its buildings to crumble, with vegetation gradually reclaiming the site. Descendants of former residents are still campaigning for the return of the expropriated land and the village's reconstruction.

What is the history behind Tiermas?

Before it was emptied of people, Tiermas was known chiefly for a spa built around natural thermal springs. The tradition of bathing here for health reasons goes back to Roman times, when the sulphurous, saline and alum-rich waters were valued for their supposed curative properties. In the 19th century the spa was expanded with a substantial building of more than fifty rooms and a bathing gallery, and in 1910 the Hotel Infanta Isabel opened to serve visitors coming to take the waters.

What is left to see today?

The Tiermas landscape today is a mix of ruins and nature: standing wall fragments, remnants of the old spa complex, and sweeping views over the Yesa reservoir and the hills of the Jacetania comarca. It appeals to travellers drawn to unusual, abandoned corners of Spain rather than conventional tourist infrastructure — there are no shops or services on site, since the settlement is uninhabited.

When is the best time to visit?

Water levels in the Yesa reservoir vary through the year, and they typically drop lowest in autumn, during September and October. At that point the old thermal springs re-emerge above the waterline, with temperatures that can exceed 40°C, drawing visitors keen to bathe in the same waters people came to for centuries. It is the clearest chance to see Tiermas in a very different light from the rest of the year, when part of the site sits underwater.

How do you get to Tiermas?

Tiermas lies within the municipality of Sigüés, in the Jacetania comarca, on the border between the provinces of Zaragoza and Navarre. The surrounding area is typical Pyrenean foothill country — quiet, sparsely populated, and dotted with traces of settlements reshaped by 20th-century hydraulic projects. Visitors usually arrive via local roads running alongside the Yesa reservoir, often combining a stop at Tiermas with visits to the region's other abandoned villages.

Frequently Asked Questions

Does anyone live in Tiermas? No, the settlement is completely uninhabited. Residents were relocated when the Yesa reservoir was built, and the village has stood empty for decades.

Why was Tiermas historically significant? Because of its spa built around natural thermal springs, known since Roman times and expanded in the 19th and early 20th centuries, including the Hotel Infanta Isabel.

Can you still bathe in the hot springs here? Yes — when the Yesa reservoir's water level drops, usually in autumn, spots with naturally warm water are exposed and can be used for bathing.

Where exactly is Tiermas located? In the municipality of Sigüés, in the Jacetania comarca, Zaragoza province, on the Aragón river next to the Yesa reservoir, close to the border with Navarre.