The Great Wall of China

The Great Wall of China is a sequence of stone and earthen fortifications in China, built between 5th century BC and the 17th century to guard the northern borders of the Chinese Empire for the period of the rule of successive dynasties. Several walls, referred to as the Great Wall of China, were built since the 5th century BC, the most well-known being the one built between 220 BC and 200 BC by the first Emperor of China, Qin Shi Huang; this wall was situated much further north than the current wall built during the Ming Dynasty, and little of it remains.
The Great Wall is one of the existing megastructure and the world's longest man-made structure, stretching over 6,352 km (3,948 miles) from Shanhai Pass in the east to Lop Nur in the west, along an arc that about delineates the southern edge of Inner Mongolia.