The event that marked the beginning of the post-war era in the U.S. was World War II's conclusion in 1945. After the war, the U.S. emerged as a global superpower, leading to significant economic growth and a shift in international relations. This era saw the rise of the Cold War, the establishment of the United Nations, and the proliferation of consumer culture. The aftermath also catalyzed movements for civil rights and decolonization globally, fundamentally altering the political landscape. This period laid the groundwork for contemporary U.S. foreign and domestic policies, influencing subsequent decades.