It may just look like a river crossing, but history and imagination flow through the Nanjing Yangtze River Bridge's veins of iron and steel

As grand structures go, the Nanjing Yangtze River Bridge has an unenviable job competing for public attention, and perhaps even affection, with the likes of the Great Wall of China and the Oriental Pearl Tower in Shanghai.

In fact to those ignorant of the bridge's history it may not seem that remarkable. It was, after all, only the third bridge to be built over the great Yangtze, a couple of dozen bridges in China are longer, and its specifications may otherwise seem modest.

Yet the sum of the Nanjing Yangtze River Bridge's importance far exceeds the number of its nuts and bolts, and few other man-made structures built since New China was founded in 1949 can rival it for political significance.

Indeed, for generations of Chinese, the double-decker bridge, whose construction was completed 50 years ago, has become the symbol of a collective memory and national pride. It was the first bridge over the Yangtze designed and built by China without foreign assistance.