The proof may be in the weight as China's drove a 2 ton SUV over it's glass bridge. The Zhangjiajie Grand Canyon Bridge under went the testing to prove to the people and the media that the glass made bridge can stand the weight test without breaking. Many speculators were curious and very hesitate in walking on the glass flooring feeling insecure it would not break. Although the glass bridge has shown some cracking in the surface its considered normal for glass surfaces, but the stronghold did not snap loose and trying to convince journalists and the people it's no danger to give way. Other demonstrations included beating the bridge with a sledge hammer. The bridge is made of 3 layers of glass 3 mm by 4.5 and 15mm thick.
