Combined photo shows pictures of the construction site of the Five-hundred-meter Aperture Spherical Telescope (FAST) at a karst valley in Pingtang County of southwest China's Guizhou Province taken respectively on May 25, 2009 (L, up), Sept. 6, 2011 (R, up), Aug. 5, 2012 (L, Center), May 2, 2014 (R, Center), Jan. 16, 2015 (L, down) and July 3, 2016. (The first five pictures are provided by the National Astronomical Observatories of Chinese Academy of Sciences and the last is taken by Xinhua photojournalist Ou Dongqu). Installation was completed on the world's largest radio telescope on Sunday morning as the last of 4,450 panels was fitted into the center of the big dish. Scientists will then begin debugging and trial observation of the FAST. The project has the potential to search for more strange objects to better understand the origin of the universe and boost the global hunt for extraterrestrial life. (Xinhua)