Impressive and well-preserved fortification close to Perillos, built in 1497 by Ferdinand the Catholic of Aragon.

After the Treaty of the Pyrenees was signed, it came into French hands and was the home of Vauban. The castle, and the route it protects before that played a strategic role in a large number of wars thought the centuries, ranging from Hannibal to the 30-year war. The kings of Aragon feature in the Perillos mystery these days, but already in the 1960’s, French adventurer and writer André Malraux tried to get the building plans, specifically to get information about the subterranean waterways and chambers of the fort. According to a local of Opoul-Perillos, the wood that was used for the fort came from Perillos. The area, never recovered and changed into the wasteland we know today.

It is said that this is the place where the underground stream ends that begins beneath Mount Bugarach.