A rare copy of the U.S. Constitution laid forgotten inside a filing cabinet. Now, it could sell for millions at auction.

The rare piece of American history — the only U.S. Constitution of its kind thought to be in private hands – will go up for auction by Brunk Auctions on Sept. 28 in Asheville, North Carolina. The minimum bid for the auction of $1 million has already been made and it is expected to go for a much higher price tag.