A rare 1975 San Francisco Mint dime sold for a whopping $506,250 in an online auction. This ultra-rare coin is one of only two known examples without the distinctive "S" mark indicating its origin from the San Francisco Mint. The dime was previously owned by three anonymous sisters in Ohio who inherited it after their brother's passing.

Source: https://www.popsci.com/science/san-francisco-mint-dime/