Which New York City museum was designed by Marcel Breuer in a Brutalist style?

The New York City museum designed by Marcel Breuer in a Brutalist style was the Whitney Museum of American Art.

Breuer designed the Whitney’s distinctive Madison Avenue building in Manhattan, which opened in 1966. Its inverted, top-heavy shape, rough concrete surfaces and deeply recessed windows made it a landmark of postwar museum architecture and one of Breuer’s most important works in New York.

The building was created specifically for the Whitney, whose collection and exhibition programme had outgrown its earlier premises. After the Whitney moved downtown in 2015, the former museum building became known as the Breuer Building. It was later used by the Metropolitan Museum of Art as the Met Breuer before passing to other cultural and commercial uses.

The answer is sometimes confused with the Guggenheim Museum, also a famous New York art museum, but that building was designed by Frank Lloyd Wright. Breuer’s building is also often identified by its address, 945 Madison Avenue, rather than by its later institutional names.