A 1918 U.S. 24-cent airmail stamp became rare and valuable because its airplane image was printed upside down.
Notes on verification
Confirmed by Smithsonian National Postal Museum, Smithsonian Magazine, and NBC News, all corroborating the printing error, rarity, and high market value of the Inverted Jenny stamp. [tier=silver indep_score=0.875 clusters=2 claim_tier=notable]
Sources
- Philately - Notable Stamps, Collections | Britannica (seed:culture_and_philosophy)
- https://postalmuseum.si.edu/topics/inverted-jenny (corroboration)
- https://www.smithsonianmag.com/smithsonian-institution/how-inverted-jenny-24-cent-stamp-came-be-worth-fortune-180969090/ (corroboration)