The Seagram Building
Credit: John Lamparski / Getty Images

The Seagram Building may not be the most visited skyscraper in Manhattan – that honor goes to the Empire State Building – but it is almost certainly the most architecturally significant. Designed by ur-modernist Ludwig mies van der Rohe, one of the creators of the so-called "international style" that brought stately practicality into vogue in the late fifties, and his disciple Phillip Johnson, well known for his stunning "Prairie House," 375 Park Avenue is a restrained building that embraces glass and steel as design features instead of studiously avoiding ornamentation of any kind. Unlike similar office buildings, the Seagram Building does not take up every available inch or the land it stands on. Rather than being a continuation of the urban corridor, his building is a towering citadel on an island. It's pillared base and straight sides have also made it one of the most imitated buildings on the planet.