The Great Wall of China is a series of stone, brick and wood fortifications built along the historical northern borders of China to protect the Chinese states and empires against the raids and invasions of the various nomadic groups of the Eurasian Steppe. Several walls were being built as early as the 7th century BC and were later joined together and made bigger and stronger. The especially famous part of the wall was built in 220–206 BC by Qin Shi Huang, the first Emperor of China. Little of that wall remains. The majority of the existing wall is from the Ming Dynasty (1368–1644).
The wall with all of its branches measures out to be 13,171 miles, and is today recognized as one of the most impressive architectural feats in history.