Smithsonian Cooper-Hewitt, National Design Museum
Located in the former home of Andrew Carnegie, the Cooper-Hewitt Museum is itself a National Historic Landmark. It is the only museum in the United States that is solely dedicated to both historic and contemporary design. Make sure to check out Color Moves: Art and Fashion by Sonia Delaunay to see some gorgeous textiles and garments straight from Paris.
Smithsonian Cooper-Hewitt, 91st Street and Fifth Avenue
[Photo via @shopcooperhewitt]