The New-York Historical Society
Architects: York & Sawyer, Walker & Gillette
Address: 170 Central Park West, Manhattan
Now over 100 years old, the New-York Historical Society (don't forget the hyphen!) has a veritable warehouse of art and objects of all things New York. Architecturally it's a bit of a sleeper building on Central Park West, kind of overshadowed by the American Museum of Natural History, as well as all those great residential buildings, but it's actually a subtle jewel with its original colonnaded central section and beaux-arts pavilions on either end. It's also got a great collection of Hudson River School paintings.