Photo de stock - The Citadel of Aleppo is a large medieval fortified palace in the centre of the old city of Aleppo, northern Syria. It is considered to be one of the oldest and largest castles in the world. Usage of the Citadel hill dates back at least to the middle of the 3rd millennium BCE. Subsequently occupied by many civilizations including the Greeks, Byzantines, Ayyubids and Mamelukes, the majority of the construction as it stands today is thought to originate from the Ayyubid period.<br/><br/> Aleppo, the second city of Syria and quite possibly the longest continually inhabited settlement in the world, is of venerable age. So old, indeed, that its Arabic name, Halab, is first mentioned in Semitic texts of the third millennium BCE. Situated in the north-west of the country, just a few kilometres from the Turkish frontier, Aleppo is located at the confluence of several great trade routes and, as a city of commerce, has always been rich.