Designed around 1900 by architect Hector Guimard, this art nouveau subway design has been defining Parisian streetscapes ever since – over 80 of these elegant gateways survive. This original example now holds court in the sculpture garden at the National Gallery of Art in Washington, DC, sharing the stage with works by Alexander Calder, Tony Smith, Claes Oldenberg, George Rickey and Roy Lichtenstein.