I wanted to see the Citadel because it seems that from wherever you are in Cairo, you can see the Citadel and the Mosque of Mohammed Ali, which dominates the skyline. I got there early one morning and I have to say I was very disappointed. Apart from a fantastic view of the surrounding city, there wasn't much of interest to be seen. The mosque itself, though certainly grand in scale, is not very beautiful. The interior of the mosque is interesting, but it's hardly worth the effort. I would say that it's better to take a picture of it on the horizon than to take the time to go all the way up the hill. It's certainly not worth the entrance fee.