The Great Wall of China is said to be the only man-made object visible 1 the Moon. This belief has persisted 2 today, sometimes even entering school textbooks. This belief might go 3 to the fascination with the “canals” once believed to exist on Mars. The logic was simple: if people on Earth can see the Martians' canals, the Martians might be able to see the Great Wall. But in fact, the Great Wall is only a few meters wide — similar 4 size to highways and airport runways — and is about the same color as the soil surrounding it. It cannot be seen by the unaided eye from the distance of the Moon, much less from Mars. If the Great Wall were visible from the Moon, it would also be apparent from near-Earth orbit, but from there it is barely visible, and only 5 nearly perfect conditions. The Great Wall of China is no more conspicuous from outer space than many other man-made objects.