The domes of King Fahd's expansion in the Prophet's Mosque is considered an architectural masterpiece and engineering design that brings together an enormous construction design, exquisite decorations and inscriptions, and a smooth motion through automatic control. The dome that weighs 80 tons is designed to move a few seconds at scheduled times. As many as 27 moving domes are periodically maintained in the Prophet's Mosque regularly and installed on a square base with a side length of 18 meters, each weighing 80 tons, and moving on iron axes with a total length of 1573 meters. The internal structure is coated with layers of solid cedar wood, each layer with a thickness of 2 mm, and ornamented with distinctive wooden shapes and pieces of blue turquoise. The external structure is covered with pieces of small hexagonal ceramic mosaic with a diameter of 70 mm. The domes are decorated with geometric shadow lines in turquoise and light beige colours. The domes of the Prophet's Mosque are manufactured to open and close automatically through control devices; to maintain the cool air inside the mosque and help provide a suitable climate for worshippers.
