Workers check the guardrail at the construction site of a vitreous bridge above the grand canyon in Zhangjiajie, central China's Hunan Province, June 15, 2015. A giant new vitreous bridge is currently under construction across the 400-metre deep Zhangjiajie Grand Canyon in Hunan province. The bridge will stretch 430 metres between its support pillars, making it a new scenic spot for tourism in the world. (Xinhua/Long Hongtao)