In 2015, Nancy Carlson, a Chicago resident, bought a bag used by Neil Armstrong during the first mission to the moon (he put moon dust in it, of which traces still remain) for $995.

On Thursday, the 48th anniversary of the Apollo moon landing, she sold that bag for $1.8 million at a Sotheby’s auction in New York City (pre-sale estimates had the bag fetching between $2 million and $4 million).

“Nearly all of the equipment from that historic mission is housed in the US National Collection at the Smithsonian,” Sotheby’s category note reads. “This is the only artifact available for private ownership.”

It’s on sale today because of a mixup, reports the New York Times. In 2003, investigators found the bag in a garage, specifically the garage of then-Kansas museum manager Max Ary (he was later convicted of stealing artifacts from the museum). The bag was mislabeled, and put up for sale on a government auction, where it received no bids until finally, at its third auction, Carlson purchased it for $995.

NASA caught wind of the mistake when Carlson sent the bag to the space agency for authentication. Realizing how valuable (and historically significant) the bag was, NASA kept it—which resulted in a court battle. In February, a U.S. District judge ordered the agency to return the bag to Carlson. In a statement, NASA expressed its regret about the decision, saying the bag was “never meant to be owned by an individual” as it belongs to the “American people and should be on display for the public.”