General view of the mosque of Ibn-Tulun from the North-East. The furthest westerly evidence of the spread of the Abbasid imperial style in its decoration, its construction material, and its minaret, this mosque is perhaps the most serene structure in Cairo. It is distinguished by its brick piers with four engaged brick columns on the four sides (a combination of eastern and western influences), its angularly spiralling minaret, and its ziyadas, or open extensions which ring it on three sides and work as buffers between the streets’ bustle and the religious space inside.