The Relliguer Cave is an underground gallery carved into the granite rock at the foot of the castle. The entrance is located within the medieval enclosure, very close to one of the main gates in the walls, the Barcelona Gate, and also near the medieval fortified path connecting the town to the fortress, the former castle. The cave is a hypogeum consisting of a 26-metre passageway that descends to a small chamber at a depth of six metres. It may have been used as a shelter and hiding place in times of danger or as a gallery related to the fortification of the hill.