This is a description of the Great Wall of China, a monumental structure built over 2,000 years ago to protect the Chinese Empire from invasion. It is the longest man-made structure in the world, stretching over 5,500 miles from east to west. The wall is made of stone
From Wikipedia
The Great Wall of China is a series of fortifications in China. They were built across the historical northern borders of ancient Chinese states and Imperial China as protection against various nomadic groups from the Eurasian Steppe. The first walls date to the 7th century BC; these were joined together in the Qin dynasty. Successive dynasties expanded the wall system; the best-known sections were built by the Ming dynasty (1368–1644).