In the mountains of southwestern Guizhou Province in southwest China, the Huajiang Canyon Bridge arcs across a steep gorge like a "steel rainbow." With its deck 625 meters above the water, it holds the world record for deck height. Its main span of 1,420 meters also makes it the world's largest mountain-span bridge. The structure is a stunning display of China's engineering breakthroughs across one of the Earth's most rugged chasms.