(151213) -- CHICAGO, Dec. 13, 2015 (Xinhua) -- People take photos at the famous Cloud Gate in Millennium Park in Chicago, the United States on Dec. 12, 2015. Cloud Gate is British artist Anish Kapoor's first public outdoor work installed in the United States. Inspired by liquid mercury, the sculpture is among the largest of its kind in the world, measuring 66-feet long by 33-feet high, according to introduction from the city of Chicago's official website. (Xinhua/He Xianfeng)