The Hassan II Mosque (Arabic: مسجد الحسن الثاني), located in Casablanca is the largest mosque in Morocco and the fifth largest mosque in the world after the Masjid al-Haram (Grand Mosque) of Mecca and the Al-Masjid al-Nabawi (Prophet's Mosque) in Medina. Designed by the French architect Michel Pinseau and built by Bouygues. It stands on a promontory looking out to the Atlantic, which can be seen through a gigantic glass floor with room for 25,000 worshippers.

Source: Wikipedia - The Hassan II mosque