China is home to the Great Wall, the connected fortifications built to protect northern China.
The wall is not one continuous structure from one period. Several Chinese states built defensive walls before the Qin dynasty, and Qin Shi Huang linked sections after unifying China in 221 BC. Later dynasties expanded or rebuilt parts of the frontier defenses.
The best-preserved sections date mainly from the Ming dynasty, which ruled from 1368 to 1644. These sections used brick and stone, with watchtowers and gates positioned along important routes.
A common mistake is saying the Great Wall is visible from the Moon with the naked eye; that claim is unsupported. The wall’s full route includes many vanished or damaged sections, and its total length is measured by surveyed remains rather than one unbroken wall.