1. The Great Wall of China is a series of fortifications made of stone, brick, tamped earth, wood, and other materials.
2. It is built along an east-to-west line across the historical northern borders of China.
3. It was built to protect the Chinese states and empires against the raids and invasions of the various nomadic groups of the Eurasian Steppe.
4. It was built by Qin Shi Huang, the first Emperor of China. Little of that wall remains.
5. The Great Wall has been rebuilt, maintained, and enhanced over various dynasties.
