The Star-Spangled Banner National Historic Trail traces the War of 1812 in the Chesapeake, where tangible evidence of the war and stories of its people and events reveal its far-reaching impacts on this country and the world. After a 25-hour bombardment, soldiers at Fort McHenry raised a large American flag early on September 14, 1814. That flag, signaling British retreat, inspired Francis Scott Key to pen the words that became America's national anthem, The Star-Spangled Banner.