The castle of Foix dominates the city from the top of its rock. The fortress, which was part of the Cathar castles, constituted a favored refuge at the time of their persecution. It controlled access to the upper valley of the Ariège department and watched over the low country, allowing important protection behind its walls. Like most fortified castles in Ariège, the Château de Foix dates from times of constant insecurity and robbery. Such parameters encouraged its construction on a strategic location that also allows monitoring the passage point of the Pyrenees chain against potential invasions.