The Great Wall of China is a series of stone and earthen fortifications in northern China, built originally to protect the northern borders of the Chinese Empire against intrusions by various nomadic groups such as the Xiongnu from the north and rebuilt and maintained between the 5th century BC and the 16th century.
The most comprehensive archaeological survey, using advanced technologies, has recently concluded that the entire Great Wall, with all of its branches, stretches for 8,851.8 km (5,500.3 mi). This is made up of 6,259.6 km (3,889.5 mi) of sections of actual wall, 359.7 km (223.5 mi) of trenches and 2,232.5 km (1,387.2 mi) of natural defensive barriers such as hills and rivers.
As many as 1 million workers died building the Great Wall of China. It’s been called the “longest cemetery on Earth.”
Great wall of china is one of the man made element that can be viewed from the Space.