The most valuable Roosevelt dime of all is the 1975 No-S proof, and that's because of a very rare minting mistake. In fact, it's one of the rarest US coins that exists, and there are only two known ...

A coin with dates that span two World Wars, the Great Depression, and more than three decades of American history, the Mercury dime is an icon of the early 20th century. It can also be worth a lot.