The Great Wall of China is famous for being the largest man-made structure in the world.
it is known to the Chinese people as the Long Wall of Ten Thousand Li.
One li is about half a kilometer.
Many people think the Great Wall of China is just one long wall.
But today's Great Wall is really a collection of different sections of wall built in different places.
At first, the wall was built of stone, wood, grass, and earth.
In later years, the builders used bricks to make the old walls stronger and make new walls last longer.