Answered by Mr.Maki from U.S.A | Aug. 12, 2009 19:35
Many are familiar with the claim that the Great Wall of China is the only man-made object visible from space or from the moon with the naked eye. This is simply not true.
From a low orbit of the earth, many artificial objects are visible on the earth, such as highways, ships in the sea, railroads, cities, fields of crops, and even some individual buildings. While at a low orbit, the Great Wall of China can be seen from space but it is not unique in that regard.
Furthermore, when leaving the earth's orbit and acquiring an altitude of more than a few thousand miles, no man-made objects are visible at all. NASA says, "The Great Wall can barely be seen from the Shuttle, so it would not be possible to see it from the Moon with the naked eye." Thus, it'd be tough to spot the Great Wall of China or any other object from the moon. Furthermore, from the moon, even the continents are barely visible.