You can check this out in:wikitravel.org/en/Aleppo
''The citadel sits on a hill in the center of the city and is visable from almost anywhere. Usage of the Citadel hill dates back at least to the middle of the 3rd millennium BC, but the current structure dates from the 13th century. There are tours daily. It costs 150 SP to enter or 10 SP with a student card, as of November 2007. Once inside, there are no signs or explanations of the site so a guidebook is handy. There is a cafe inside the Citadel.''
The place is quite amazing!
Especially on a friday at prayer time.
You should take a turkish coffee in that cafe inisde the Citadel