American Revolution: The war fought between Great Britain and the thirteen British colonies in North America from 1775 to 1783.
Civil War: The conflict between the Northern states (Union) and the Southern states (Confederacy) from 1861 to 1865 over issues including slavery and states' rights.
Progressive Era: A period of reform and activism during the late 19th century to early 20th century aimed at improving social conditions, addressing corruption, and promoting government intervention.