The main ingredient of a Moscow mule cocktail is vodka. This cocktail combines vodka with ginger beer and lime juice, creating a refreshing drink that is particularly popular in warmer climates. Traditionally, it is served in a distinctive copper mug, which not only adds to its aesthetic appeal but also helps keep the drink cold. The Moscow mule's roots can be traced back to the 1940s in the United States, and its rise in popularity is often attributed to its unique flavor profile and presentation. The combination of spicy ginger and tart lime makes the Moscow mule a favorite in cocktail culture.