Since at least 1895, people have claimed you can see the Great Wall from the Moon. You can't.
The wall is too narrow. From the Moon, it would look like a human hair seen from 3 kilometres away.
Astronauts circle Earth just a few hundred kilometres up. From there, NASA says the wall is barely visible, and only in nearly perfect conditions. China's first astronaut, Yang Liwei, said he couldn't see it.