On a hilltop above the city is the medieval Citadel fortress, site of Muhammad Ali Mosque, an Ottoman landmark. It overlooks the Islamic Cairo neighborhood, whose zigzagging streets feature significant architecture like the 10th-century Al-Azhar Mosque and massive Bab Zuweila gate. It’s also home to the buzzing Khan el-Khalili bazaar and the Museum of Islamic Art. Highlights of the Coptic Cairo area include the Roman-era Fortress of Babylon, Hanging Church and Coptic Museum, which displays antiquities of Christian Egypt. After dark, social life thrives in countless ahwas, or coffeehouses.