One Liberty Plaza, formerly the U.S. Steel Building, is a skyscraper in Lower Manhattan, in New York City, at the location of the former Singer Building and the former City Investing Building. One Liberty Plaza is currently owned and operated by Brookfield Office Properties. The building is 743 ft (226 m) tall and has 54 floors. It was completed in 1973. At 2,300,000 sq ft (210,000 m2), each floor offers almost 1 acre (0.40 ha) of office space, making it one of the largest office buildings in New York.