During America's Gilded Age, former Montana Sen. W.A. Clark made a fortune in copper mining and railroads -- and collected art. When he died in 1925, he donated hundreds of works to the Corcoran Gallery of Art. His reclusive youngest daughter, Huguette, was also a major benefactor of the museum, paying for a major expansion and donating millions more over the years. We consider the family's patronage and influence at the Corcoran, which is becoming part of George Washington University and the National Gallery of Art.