Citadel   One of Cairo's most popular tourist attractions. The Citadel houses a number of museums, ancient mosques and other sites. It is one of the world's greatest monuments to medieval warfare as well as a highly visible landmark on Cairo's eastern skyline.   The area where the Citadel is now located began its life, not as a great military base of operations, but as the 'Dome of the Wind' - a pavilion created in 810 by Hatim Ibn Hartama who was then the governor. This area was know for its cool breeze. Between 1176 and 1183 Salah ad-Din (Saladin) and Abbasid fortified the area to protect it from attacks by the Crusaders and since then it has never been without a military garrison.  Originally it served as both a fortress and a royal city.