Workers assemble the single-aperture spherical telescope "FAST" in Pingtang County, southwest China's Guizhou Province, March 9, 2016. A total of 3,492 reflector panels, an equilateral triangle with a side length of 11 meters each, have been installed on the frame. When it is completed in 2016, the five-hundred-meter aperture spherical telescope (FAST) will be the world's largest, overtaking Puerto Rico's Arecibo Observatory, which is 300 meters in diameter. (Xinhua/Ou Dongqu)