Ardahan Castle Ardahan Castle, located in the Halil Efendi District of the city, was constructed in the 16th century under the orders of Suleiman the Magnificent. The castle, which boasts a rectangular shape with numerous towers, was built using smooth-cut stone and Khorasan mortar, making it a unique example of masonry techniques from the era. Its polygonal shapes, well-positioned form, and similarity to the Rumeli Fortress set it apart from other castles found throughout Turkey. Excavations at Ardahan Castle have uncovered evidence of an ancient settlement dating back to the Early Bronze Age, adding to its historical significance. The castle's large gate in the west features an Arabic inscription that reads: "It was built in the name of Sultan Suleiman the Great, the son of Selim Khan, the owner of the seas and lands of the Arab, Greek, and Persian countries. Let his property remain until the end of the day." This inscription serves as a testament to the castle's importance and enduring legacy.