1927 D Saint Gaudens $20
Most of the 180,000 Saint Gaudens minted at the Denver Mint were never released and fell victim to mass meltings after 1934. It is believed that the existing pieces were directly ordered from the U.S. Treasury just prior to their release, at face value plus postage, from 1927 through early 1933. In June of 2002, Sotheby's and Stack's sold the lone legal example dated 1933 in auction. This coin was never officially released before President Franklin Roosevelt suspended the circulation of gold. That coin realized $7.59 million and became the highest valued coin ever to trade at public auction.