The Great Wall of China isn't actually visible from space with the naked eye

The claim predates spaceflight by two centuries, an English writer floated it in 1754, and a 1932 Ripley's Believe It or Not cartoon called it the only man-made structure visible from the Moon. Apollo astronauts saw no sign of it from lunar distance, and even from low Earth orbit it's only marginally visible under near-perfect lighting and weather, no more so than many roads or airport runways. Seeing it takes visual acuity roughly 17,000 times sharper than average.

— NASA and astronaut observational accounts, Artificial structures visible from space — Myth traced to an unverified 1754 claim; debunked by Apollo-era observation

One credited idea per card. No filler. Swipe the rest in Savvy.

Keep swiping — it's free Works right in your browser. No app store needed.

More History

All History cards →
More from NASA →

Five ideas worth knowing, every week

The week's best cards and a puzzle, credited as always. Free, unsubscribe any time.