Caldes Castle was built on the site of ancient Roman baths in the mid-12th century. Three circular towers have survived, along with a section of the wall, two heavily altered buildings and, possibly, the hermitage of Sant Grau. During the 18th century, its interior was divided into several dwellings, and in the following century most of these partitions were removed to accommodate the former Aigua Imperial bottling plant. The castle buildings housed the Caldes healthcare centre until 2009 and now contain a heritage research and interpretation centre. On the outskirts of the town stands another castle which, according to the legend that gave the town its name, was home to a feudal lady popularly known as the “mala vella” (“wicked old woman”).