One57, formerly known as Carnegie 57 (nicknamed "The Billionaire Building"), is a 75-story (marketed as 90-story) supertall skyscraper at 157 West 57th Street in the Midtown neighborhood of Manhattan, New York City. Upon completion in 2014, it stood at 1,005 feet (306 m) tall, making it the tallest residential building in the city for a few months until 432 Park Avenue was constructed. The building has 92 condominium units on top of a new Park Hyatt Hotel with 210 rooms, which is set to become the flagship Hyatt property.
The contractor is Lend Lease Project Management & Construction, and the developer is Extell Development Company. As of January 2015, it is home to the most expensive residence ever sold in New York City.