In 1947, a Pittsfield, Massachusetts, teenager found one of the rarest coins in circulation in his lunch change.
Don Lutes Jr. was 16 when he found a 1943 Lincoln penny, one of the few made in copper.
As a coin collector, Lutes kept the penny up until his death last year, despite being told it was a fake and worth nothing -- even being told by the Treasury Department that the penny couldn't have been copper.
According to Heritage Auctions, Lutes was old enough to remember steel cents made at the time, so the copper penny stood out to him. It turned out to have been one of the most valuable coins of all time.
CNN reported the coin sold for $204,000 at the auction, which ended Thursday.
The Lincoln penny was made at a time when the U.S. mint was supposed to only be producing zinc-coated steel to save copper for the war effort. Only a handful of the copper ones were minted.
Sarah Miller, director of numismatics for Heritage Auctions' New York office, told CNN Lutes wanted proceeds from the penny to go to Berkshire Athenaeum, his hometown's public library.