Tourists wait to set foot on the Zhangjiajie Grand Canyon's glass-bottom bridge in Zhangjiajie scenic spot, central China's Hunan Province, Aug. 20, 2016. Zhangjiajie Grand Canyon's glass-bottom bridge was put into trial operation here on Saturday. Spanning two cliffs in the canyon area, the bridge stretch 430 meters long and 6 meters wide, hovering over a 300-meter-deep valley. The bridge deck is paved with transparent glasses and can accommodate up to 800 people at a time. (Xinhua/Long Hongtao)