The Hassan II Mosque or Grande Mosquée Hassan II is a mosque in Casablanca, Morocco. It is the largest mosque in Morocco and the 13th largest in the world. Its minaret is the world's tallest at 210 metres (689 ft). Completed in 1993, it was designed by Michel Pinseau and built by Bouygues. The minaret is 60 stories high topped by a laser, the light from which is directed towards Mecca. The mosque stands on a promontory looking out to the Atlantic Ocean, worshippers can pray over the sea but there is no glass floor looking into the sea. The walls are of hand-crafted marble and the roof is retractable. A maximum of 105,000 worshippers can gather together for prayer: 25,000 inside the mosque hall and another 80,000 on the mosque's outside grounds.

The mosque rises above the Atlantic Ocean. The building is built partially on land and partially over the ocean. This siting was accomplished by creating a platform linking a natural rock outcrop reclaimed from the sea, where a swimming pool had previously been located. Two large breakwaters were also built, to protect the mosque from the erosive action of the ocean waves, which can be up to 10 metres (33 ft) in height. A temporary pier 800 metres (2,600 ft) in length had to be erected to protect the foundations of the pillars from the sea during the construction period. Its environmental advantage is that it is free of noise and pollution and receives a fresh breeze from the sea.

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