Rockefeller Center is a group of buildings covering 22 acres (89,000 m2) between 48th and 51st streets in New York City, New York, United States. The buildings connect together underground. An ice-skating rink is located in the middle. The Rockefeller Center was made by John D. Rockefeller, Jr. during the Great Depression in the 1930s between Fifth Avenue and Sixth Avenue. Construction finished in 1939. It became a National Historic Place in December 1987. An extension was added west of Sixth Avenue in the 1970s.