DVD. Global Treasures. 10 Minutes. Great Wall of ChinaThe Great Wall of China, a combination of many walls, extends for 1,500 miles and winds across Northern China from Gansu Province to Hebei Province on the Yellow Sea and was constructed as a defence against the northern nomads. Although it was to be of little military significance, the Great Wall is a monument to human endeavour and relentless achievement, a meandering Man made structure that seems to connect all of China's endless horizons. Some of its towers served as the soldiers' living quarters and also played an essential role in communicating messages. The advance of hostile troops was signalled with large fires and cannon shot and any relevant military information was then communicated from tower to tower until it reached a fortress close to the capital of Beijing.