New York State Building / Queens Museum of Art
The New York State Building is the sole surviving structure from the 1939 World's Fair and is largely intact except for some tawdry exterior "updates" that were probably added for the 1964 fair. It briefly served as the home of the United Nations prior to the construction of the UN facility in Manhattan. It currently is incongruently home to a skating rink and the Queens Museum of Art. The QMA is perhaps most notable as the home of the Panorama of the City of New York, a scale model of every building in NYC that was built for the 1964 fair and last updated in 1992.