"The shot heard 'round the world" refers to the first gunfire that sparked the American Revolutionary War on April 19, 1775, at the Battles of Lexington and Concord. This phrase symbolizes the beginning of open conflict between the thirteen American colonies and British forces. The shots fired during these confrontations marked a pivotal moment, signaling the colonies' shift from peaceful protest to armed resistance. This event galvanized support for the revolution and led to a broader struggle for independence. The phrase has since become emblematic of revolutionary movements around the globe, highlighting the impact of individual acts on history.