National Moscow Mule Day is observed on March 3 every year in the United States, Canada, and the United Kingdom, celebrating the classic cocktail known for being served in a copper mug. The Moscow mule, made with vodka, ginger beer, and lime juice, was created in 1941 by Jack Morgan, John G. Martin, and Rudolph P. Kunett during a discussion about low sales at a bar in New York. The introduction of the copper mug is credited to Sophie Berezinski, who brought them to the U.S. and offered them to Morgan for his pub. The holiday, established by the Smirnoff vodka brand, highlights the three primary ingredients of the cocktail, which are represented by the date 3/3. Celebrations typically involve enjoying a Moscow mule, either at bars or made at home, and sharing the occasion on social media using specific hashtags. Variations of the cocktail have emerged, reflecting different liquors, and some bars have renamed the classic version to protest geopolitical events.