The Answer:
Nope.
The original formulation of this claim—which predates space
travel—was that the Great Wall of China was the only manmade structure
that could be seen from the moon.
It cannot, in fact, be seen from the moon, at least not with the
naked eye. At some lower altitudes it might be visible from outer
space, especially with the use of binoculars, but it's hardly the most
visible manmade object. While the wall is long, it is only a few
meters wide, and it's not very different in color from its
surroundings.
For more on this specific issue, see What's
Really Visible from Space at Space.com. Otherwise, you might
be interested in more Famous
Buildings and Structures.
—The Editors