The phrase "The shot heard 'round the world" is famously associated with the Battle of Lexington and Concord, which occurred on April 19, 1775. This battle marked the beginning of the American Revolutionary War between the American colonies and British forces. The phrase symbolizes the start of the struggle for American independence and has come to represent the impact of a seemingly small event that can trigger widespread consequences. It emphasizes the momentous nature of the conflict, as the skirmish ignited a war that ultimately led to the founding of the United States.