The aqueduct of Fréjus was built in the middle of the first century after the ramparts were in place. It functioned for 450 years until the 5th century. It is 42 km long, with a difference in altitude between the highest spring of Neïssoun and the castellum aquae in the city of 481 m. The aqueduct runs mostly in a covered conduit for 36.4 km and for 1.8 km on bridges and 500 m on walls. Large parts of the aqueduct are still well preserved.
References:The Château de Foix dominates the town of Foix. An important tourist site, it is known as a centre of the Cathars. Built on an older 7th-century fortification, the castle is known from 987. In 1002, it was mentioned in the will of Roger I, Count of Carcassonne, who bequeathed the fortress to his youngest child, Bernard. In effect, the family ruling over the region were installed here which allowed them to control access to the upper Ariège valley and to keep surveillance from this strategic point over the lower land, protected behind impregnable walls.
In 1034, the castle became capital of the County of Foix and played a decisive role in medieval military history. During the two following centuries, the castle was home to Counts with shining personalities who became the soul of the Occitan resistance during the crusade against the Albigensians.