18 Wonders of the World

Great Walls of China

The Great Wall of China is a series of fortifications made of stone, brick, tamped earth, wood and other materials generally built along an east-to-west line across the historical northern borders 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 built as early as the 7th century BCE, these later joined together and made bigger and stronger. Other purposes of the Great Wall have included border controls, allowing the imposition of duties on goods transported along the Silk Road, regulation or encouragement of trade and the control of immigration and emigration.