Buffalo nickel
Beginning in 1911, the Mint began work to replace the Liberty head design, and a new design, which became known as the Buffalo nickel, went into production in February 1913. Although no 1913 Liberty head nickels were officially struck, five are known to exist. While it is uncertain how these pieces originated, they have come to be among the most expensive coins in the world, with one selling in 2018 for $4.5 million