Mosquée Hassan II

Completed in 1993, the Hassan II Mosque is Morocco's largest mosque and one of the biggest in the world, with a minaret reaching 210 meters — the tallest of any religious building. Built partly over the Atlantic Ocean, its prayer hall can hold 25,000 worshippers, and it is one of the few Moroccan mosques open to non-Muslim visitors via guided tour. A retractable roof and heated floor make it as much a feat of engineering as a place of worship.