Moscow Mule, also known as a Vodka buck, is a cocktail made with a high-quality vodka, a spicy ginger beer, and lime juice, garnished with a slice or wedge of lime. It is usually served in a copper mug. The cocktail became popular during the vodka craze in the United States during the 1950s. The cocktail was invented in 1941 by John G. Martin and Jack Morgan.