Cairo Citadel

Originally built by Saladin in the 12th century on a high ridge over Cairo. It served as the seat of government until the 19th century. Various rulers added to the fortress complex over the years. Unfortunately, much of the original construction was replaced in the 19th century, call it "urban renewal," including the attendant gentrification by building palaces instead of fortifications.
The 1st picture is a part of the citadel from outside. The 2nd is the prison museum. At least it isn't a dungeon. It is a row of cells in the middle of the fortress, some with barred doors, others with solid steel doors.
The main feature in the citadel these days is the mosque of Mohammed Ali (no, not that one). Pictures 3&4 are the 2 courtyards around the mosque while the 5th is inside. This mosque us designed based on the Blue Mosque in Istanbul. (There is a post of the Blue Mosque among those from my 1st visit to Turkey.)
The last picture is the view over Cairo from the citadelもっと詳しく