The Citigroup Center (formerly Citicorp Center and now known as 601 Lexington Avenue) is one of the ten tallest skyscrapers in New York City, located at 53rd Street between Lexington Avenue and Third Avenue in midtown Manhattan. The 59-floor, 915-foot (279-m) building contains 1.3 million square feet (120,000 m²) of office space, and is one of the most distinctive and imposing in New York's skyline, thanks to a 45° angled top and a unique stilt-style base. It was designed by architect Hugh Stubbins and structural engineer William LeMessurier for Citibank, and was completed in 1977. The building is currently owned by Boston Properties, and in 2009, was renamed 601 Lexington Avenue.