How are the bricks used to repair the Great Wall made?

The Great Wall, one of the Seven Wonders of the World, was built more than 2,000 years ago. Regular repair work to the walls is needed to protect this symbol of Chinese civilization. The process to make the grey bricks used in the repair work is complicated. [Photo: IC]

Firstly, it's necessary to choose good quality red clay to make good grey bricks. The clay needs to be thoroughly aired, then stirred and mixed with water to make mud. [Photo: IC]

The mud is poured into a specially-designed frame to mold the brick. Workers then use tools to rub down the surface of the brick to make it smooth. [Photo: IC]

Dry soil is scattered onto the bricks to prevent them from sticking together. They are then left for 20 days to dry out. [Photo: IC]