The Great Wall of China cannot actually be seen from space with the naked eye.

Despite being one of the most repeated pieces of trivia about the wall, it isn’t true. The wall is long, but it’s also narrow — rarely wider than about 9 meters — and built from materials similar in color to the surrounding terrain, which makes it effectively invisible to the unaided eye from the roughly 400-kilometer altitude of low Earth orbit.

Astronauts, including China’s own Yang Liwei, have confirmed they couldn’t spot it without aid. Several orbiting astronauts have noted that plenty of other human structures, like airports, highways, and cities, are actually far easier to pick out from orbit than the wall itself.