Constructors work at the construction site of a glass bridge at the Grand Canyon of Zhangjiajie National Forest Park, central China's Hunan Province, April 12, 2016. The 430-meter long, 6-meter wide bridge is expected to be put into a trial operation in May. The structure has undergone nearly 100 safety tests to ensure it can support the weight of 800 people. (Xinhua/Long Hongtao)
