Near Siliqua at the entrance of the valley of the Cixerri stands the castle of Acquafredda. This castle is built on a high volcanic rock in a strategic point where it could control the movement of people and merchandise. To the west lies Iglesias, the center of the mining district, and to the east Cagliari, the main port of the island of Sardinia. To the south a road passes the mountains and reaches the southern shores near Sant'Antioco, passing by Santadi and Villaperuccio. The castle was built in the thirteenth century by the Giudici of Cagliari and passed on to the pisan family of the Donoratico. In fact one of the owners would have been Ugolino della Gherardesca Conte di Donoratico mentioned by Dante Alighieri in the Divina Commedia.
The entrance to the castle and the surrounding natural park of the Domo Andesito di Acquafredda is near the foot of the vulcanic rock. From this point a path leads up to the various levels of the castle which at it's highest point is 256 meters above sea level. On the first level a gate gives access to the fortified village, the borgo. Once the soldiers and servants lived here with their families. Remains of houses and the foudnations of a church testify this. Visible are the fortified walls and towers. Of the four towers two are still present.
The path leads further upward to the second level, a large fortified waterbassin and above that a tower that had the function of water tower at 200 meters height. The path leads to the area between the main castle to the left and a secondary tower to the right, the Torre di Guardia. The main castle was not accessible at the time of our visit, it was not secured for visitors. The tower opposite the castle could be accessed, from here there is a magnificent view of the surrounding countryside. Probably the tower and the castle were connected by a bridge as shown on a relief present in the church of Siliqua. On the outer wall of the castle there are still coat of arms visible, applied by the masters of the castle.