English: The Ketchaoua Mosque is a mosque in Algiers, the capital of Algeria. It was built during the Ottoman rule in the 17th century and is located at the foot of the Casbah, which is a UNESCO World Heritage Site. The mosque that stands on the first of the Casbah’s many steep stairways, was logistically and symbolically the cynosure of the pre-colonial city of Algiers.The mosque is noted for its unique fusion of Moorish and Byzantine architecture.