Al-Azhar Mosque in Cairo, Egypt:

Under category: Muhammad Pocket Guide

Al-Azhar Mosque in Cairo, Egypt:

Established in 971 CE, connected with one of the oldest operating universities in the world (opened 988 CE)

The Ahmad bn Tulun Mosque in Cairo, Egypt: 

Completed in 879 CE, one of the largest in the world, (26,318 m2) it is also famed for its lovely architecture and unique minaret.