This attractive mosque was built during World War II over the tomb of a 13th-century holy man, who is the patron saint of the city's fishermen. The area surrounding it has been turned into Egypt's largest and most bizarre religious/retail complex, with a cluster of mosques sharing a terrace that hides an underground shopping center. Intruding on the space is a horrific modernism-on-the-cheap office building (with yet more shops) that is as pointed and angular as the mosques are smooth and curved. If you are dressed modestly and the mosque is open, you should be able to get inside. If so, remove your shoes and refrain from taking photos.
Corniche, al-Anfushi, Alexandria, 21511, Egypt