945 Madison Avenue, also known as the Breuer Building, is a museum building in the Upper East Side of Manhattan, New York City. The Marcel Breuer-designed structure was built from 1964 to 1966 as the third home for the Whitney Museum of American Art. The Whitney moved out in 2014, after nearly 50 years in the building. In 2016, it was leased to the Metropolitan Museum of Art and became the Met Breuer, which closed in 2020. The building currently houses the Frick Madison, the temporary home of the Frick Collection set for a two-year period that began in March 2021. There are no public plans for the building after the Met's lease expires in 2023. The five story building occupies a roughly square plot at Madison Avenue and 75th Street. The building, described as Brutalist or Modernist, has exterior faces of variegated granite and exposed concrete. It has stark angular shapes, including cantilevered floors progressively extending atop its entryway, resembling an inverted ziggurat. The design, controversial though lauded by notable critics at its opening, has seen more universally positive reviews into the present day. The building is a contributing property to the Upper East Side Historic District, a New York City and national historic district.