The Chinese government says the Great Wall is 5,500 miles (8,851.8 km) long, which is 1,585 miles (2,551 km) longer than was thought. A new survey relying on GPS satellites and infrared imaging uncovered sections that were hidden by hills, trenches and rivers.
For the record: There is a longstanding myth that the Great Wall of China is the only manmade object visible from space. In reality, many human constructs can be seen from Earth orbit. Shuttle astronauts can see highways, airports, dams and even large vehicles from an Earth orbit that is about 135 miles (217 kilometers) high. Cities are clearly distinct from surrounding countryside, and that's true even from the higher perch of the International Space Station, which circles the planet at about 250 miles (400 kilometers) up.
Back in 2003, when Chinese astronaut Yang Liwei said he didn't see the Great Wall from space, many were left with the false impression that it couldn't be spotted from on high.
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