Constructed as a line of defence in 221 BC, the Great Wall is 6,000 km long, 6-8 m high and 8-10 m wide. A million labourers were forced to work on it. Tanks were able to travel along the top of the Wall which had guard towers placed every 200 m. Fires would be lit in the towers to signal when an attack was taking place. The Wall was constructed from natural resources: the materials used depended on the terrain of the area that the Wall travels through. This is what accounts for its sinewy contours. Part of the film, "Tommy Tricker and the Stamp Traveller," was shot in China.
