Salah Al-Din Citadel, 1176-1183 AD (572-579 AH). This is the largest citadel in the Islamic world and was established under the rule of Sultan Al-Din Yusuf Ibn Ayyub and constructed under the direction of Bahaa Al Din Qaraqouch. It was designed to be both a fortress and residence. Many additional buildings were added between the Ayyubid period to the rule of Mohammad Ali.

The Citadel, Cairo.