The Citadel (Al-Qalaa) is one of the most popular tourist sites in Cairo. It was originally founded in 1176 CE by the famous Muslim general Salahuddin. Contained within it are the mosques of Mohammed Ali, the Mamluk Mosque of El Nasser Mohamed, and the smaller Mosque of Suleiman Pasha El Khadim.
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References: Cairo – Cardogan guides