The assembly site of the 500-meter single-aperture spherical telescope (FAST) deep in the mountains of Pingtang county, Southwest China's Guizhou province, Aug 2, 2015. The construction of the telescope began in March 2011 in a natural, bowl-shaped valley. When it is completed in 2016, the telescope will be the world's largest, overtaking Puerto Rico's Arecibo Observatory, which is only 300 meters in diameter. (Photo: China News Service/Liu Chaorong)
