Eight blocks south of Loews Regency on Park Avenue, you'll find two works of modernist architecture that shaped the landscapes of cities around the world. The Seagram Building, seen here, was completed in 1958 and is master architect Mies van der Rohe's only building in New York. (Philip Johnson was responsible for the lobby and the building's famous Four Seasons restaurant.) A triumph of the International Style, the building is a model of restraint while its open plaza became a commonplace feature of many skyscrapers that followed. Critic Herbert Muschamp once described it as, "the millennium's most important building." Across the street, the Lever House is slightly older than the Seagram Building, having been completed in 1952. Also in the International Style, this curtain-wall skyscraper by Gordon Bunshaft of Skidmore, Owings, and Merrill launched the transformation of Park Avenue from masonry apartment buildings to gleaming corporate headquarters.