BP GEOGRAPHIC

Why is the Chinese Wall still there? It seems to be an unusual question but normally brick constructions should only last one hundred years, and the Chinese Wall in its current state was built during the early Ming dynasty in the 15th century.

The reason is not the bricks, they are standard. It is the mortar between them. Just like basically every meal it contains rice. The starch from the rice makes it extremely strong. When rice reacts with the lime it leads to smaller molecular structures which is an advantage.

Since rice is not growing in the area around the Great Wall it was imported from southern China.

Lost knowledge from the past, discovered by modern scientists.