In the parish of the same name, these springs issue some of the most mineral-rich water in Europe.

They were discovered by the Luso-Romans in the 4th century, and just to the side of the present spa you can find the vestiges of this ancient bathing complex.

The spring is highly alkaline, and is rich with sodium, sulphur compounds and fluoride.

The claim is that this makes the waters more effective at treating musculoskeletal and breathing problems.

If you only have a few hours to spare, you can soak for a short time in the thermal pool and spa’s jacuzzi and whirlpools.