The Château d'Aguilar is one of the so-called Cathar castles. The design of the castle witnesses the practical military thinking of the 12th century. The castle consists of an inner keep built in the 12th century, surrounded by an outer pentagonal fortification from the 13th century. This fortification is oriented such that its point guards the side most favourable to attackers. The keep and the inner hexagonal fortification is flanked at each corner with semi-circular guard towers, each equipped with archery outlooks. The strategic location of the castle on a hill overhanging the plain of Tuchan allows supervision of the Corbières. Despite this, the castle is easily accessible from the plains because of its relatively low elevation of 321 metres.
There is a small underground chapel of Saint-Anne below the keep.
The earliest building at this location belonged to the count of Fonnollède since 1021. In the 13th century, the keep that had replaced earlier buildings was bequeathed by the viscounts of Carcassonne to their vassal, the Ternes.
In 1210, it was invaded and occupied by Simon de Montfort, whose soldiers took and held the owner Raymond de Termes in a dark dungeon in the Carcassonne. Militarily, the castle lay dormant for the next 30 years, until Raymond's son Oliver de Termes took back the castle in the brief revolt against the crusaders. Aguilar became the refuge of many faydits, Cathar knights and lords without strongholds. In 1246, a royal garrison was installed to supervise the Aragon frontier.
Olivier, however, eventually made an alliance with king Louis IX, who purchased the castle from him in 1260. Despite the heavy fortifications, the castle would be continually under siege by opposers to the French or Spanish rulers until the 16th century.
When the border was pushed back to the south of Roussillon by the treaty of the Pyrenées, the castle gradually lost its strategic importance, and was eventually abandoned in 1569. Today it is in decrepit condition. Since 1949, it has been listed as a monument historique by the French Ministry of Culture.
Derbent is the southernmost city in Russia, occupying the narrow gateway between the Caspian Sea and the Caucasus Mountains connecting the Eurasian steppes to the north and the Iranian Plateau to the south. Derbent claims to be the oldest city in Russia with historical documentation dating to the 8th century BCE. Due to its strategic location, over the course of history, the city changed ownership many times, particularly among the Persian, Arab, Mongol, Timurid, Shirvan and Iranian kingdoms.
Derbent has archaeological structures over 5,000 years old. As a result of this geographic peculiarity, the city developed between two walls, stretching from the mountains to the sea. These fortifications were continuously employed for a millennium and a half, longer than any other extant fortress in the world.
A traditionally and historically Iranian city, the first intensive settlement in the Derbent area dates from the 8th century BC. The site was intermittently controlled by the Persian monarchs, starting from the 6th century BC. Until the 4th century AD, it was part of Caucasian Albania which was a satrap of the Achaemenid Persian Empire. In the 5th century Derbent functioned as a border fortress and the seat of Sassanid Persians. Because of its strategic position on the northern branch of the Silk Route, the fortress was contested by the Khazars in the course of the Khazar-Arab Wars. In 654, Derbent was captured by the Arabs.
The Sassanid fortress does not exist any more, as the famous Derbent fortress as it stands today was built from the 12th century onward. Derbent became a strong military outpost and harbour of the Sassanid empire. During the 5th and 6th centuries, Derbent also became an important center for spreading the Christian faith in the Caucasus.
The site continued to be of great strategic importance until the 19th century. Today the fortifications consist of two parallel defence walls and Naryn-Kala Citadel. The walls are 3.6km long, stretching from the sea up to the mountains. They were built from stone and had 73 defence towers. 9 out of the 14 original gates remain.
In Naryn-Kala Citadel most of the old buildings, including a palace and a church, are now in ruins. It also holds baths and one of the oldest mosques in the former USSR.
In 2003, UNESCO included the old part of Derbent with traditional buildings in the World Heritage List.