The Five-hundred-meter Aperture Spherical Telescope, located in southwest China (also known as the Eye of Heaven), became the largest filled-aperture radio telescope in the world upon its completion in 2016. Beating Arecibo by 200 metres (656 feet) in diameter, it sits in a natural depression in the landscape and became fully operational in January 2020. Built as a geodesic dome, it is made of 4,450 triangular aluminium panels moved by 2,225 winches to form a 300-metre (984-foot) diameter parabolic antenna facing in the desired direction. Radio waves are focused on a feed cabin suspended 140 metres (459 feet) above the dish by six support towers. It works in the 70MHz–3GHz frequency range.