West wing: 1895-97, central section and dome: 1900-05, east wing: 1904-06, staircase: 1906, remainder (not visible from Eastern Parkway): 1913-15, McKim, Mead & White
Charles Follen McKim was the original architect of what was conceived as a much larger museum than was actually built. Even in its reduced state, it ranks as one of the largest and finest museums in the country. Originally, the building featured a monumental staircase, built in 1906 and removed, under the direction of William Lescaze, in 1934-35. In 2004, Polshek Partnership Architects, with permission from the New York City Landmarks Preservation Commission, added a dramatic, multi-tiered, curving new entrance of metal and glass to the building.