The modern United States Capitol is a triumph of both engineering and design. From its 9-million-pound cast-iron dome to the dazzling opulence of the President's Room and the Senate corridors, the Capitol is one of the most renowned buildings in the world. But the history of the U.S. Capitol is also the history of America's most tumultuous years. As the new Capitol rose above Washington's skyline, battles over slavery and secession ripped the country...