The Great Wall of China is a series of fortifications made of stone, brick, tamped earth, wood, and other materials. Several walls were being built as early as the 7th century BC. Especially famous is the wall built between 220–206 BC by the first Emperor of China, Qin Shi Huang. Little of that wall remains. The majority of the existing wall was reconstructed during the Ming Dynasty. - New Seven Wonders of the World.