The Great Wall of China is the world’s longest man-made structure, stretching approximately 1,500 miles (2,400 km) along China’s northern and northwestern borders. Erected to prevent invasions by northern nomads, it is an amalgamation of many walls built in ancient times and connected by later empires. Averaging a height of 25 feet (7.6 m) and a width of 15 to 30 feet (4.6–9.1 m) at its base, the wall is fortified by watchtowers placed at regular intervals. Can the Great Wall be seen from space? Discuss
Source: The Free Dictionary