The Citadel of Aleppo is a historic fortress located in the city of Aleppo, Syria. It is one of the largest and oldest castles in the world, with origins dating back to the 3rd millennium BC. The citadel has served various purposes throughout history, including as a royal palace and military stronghold. The structure is built on a hill, providing a strategic vantage point over the surrounding area. Its impressive architecture features massive walls, towers, and a large moat. The Citadel of Aleppo is a UNESCO World Heritage Site, recognized for its cultural significance and historical importance.