Introduction to the roof of the main hall: The roof of the main hall can be opened and closed remotely. The two doors each weigh 1,100 tons. The 3,400-square-meter cedar wood movable roof can be fully opened in 5 minutes on a sunny day. Sunlight shines into the sacred prayer hall, and at the same time, together with the sea water and the foundation, it caters to the three elements of life mentioned in the Qur'an: air, water and land.