As the 19th century advanced, the White House began to seem increasingly cramped. In 1889, the centennial of the U.S. presidency, First Lady Caroline Harrison suggested adding an art wing to the east and an administrative wing to the west, with glass-enclosed palm gardens, plant conservatories, and a lily pond completing the quadrangle, creating a private inner courtyard (top). Congress shot it down. In 1900 Army engineer Colonel Theodore Bingham offered his own plan, which would add a massive two-story cylindrical wing at each flank, with domes and lanterns patterned after those at the Library of Congress (middle and bottom)....