Peace dollar (1921–1935; 1964)
Introduced in December 1921, the Peace dollar, designed by medalist Anthony de Francisci, was promulgated to commemorate the signing of formal peace treaties between the Allied forces and Germany and Austria. These treaties officially ended the Allies’ World War I hostilities with these two countries. In 1922 the Mint made silver dollar production its top priority, causing other denominations to be produced sparingly if at all that year. Production ceased temporarily after 1928; original plans apparently called for only a one year suspension, but this was extended by the Great Depression. Mintage resumed in 1934, but for only two years.
In May 1965, 316,000+ Peace Dollars were minted, all at the Denver Mint and dated 1964-D; however, plans for completing this coinage were abandoned, and most of those already minted were melted, with two known trial strike specimens being preserved (for assay purposes) until 1970, when they too were melted, and none released either for circulation or collection purposes. It is rumored that one or more pieces still exist, most notably any examples obtained by key members of Congress, the President, or mint officials. However, this coin, much like the 1933 $20 gold Double Eagle (aside from the “exception”, sold in 2002 for over $7 million), is illegal to own and would be subject to confiscation.
Article Source: en.wikipedia.org