The Roman aqueduct of Segovia was built, probably in the 1st century BC, to bring water from the mountains to the hilltop settlement of Segovia. It was a massive feat of engineering as it ran for around 15 km and had to cross a wide valley before it entered the city. It was used to bring water to the town until the 19th century.
Today the aquduct is part of a UNESCO World Heritage Site that also includes the old city and fortifications of Segovia. It is an enormous construction of masonry, 813 m in length, consisting of four straight segments and two superimposed arcades borne by 128 pillars. At the lowest point of the valley, the Aqueduct stands at a height of 28.5 m above ground. The tall arches of the aqueduct bridge are a major tourist attraction.
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.