Lake Success, NEW YORK - United Nations - Interim Headquarters - 1952 - Long Island, Nassau: Lake Success is a village and a part of Great Neck in Nassau County, New York in the United States. The population was 2,934 at the 2010 census. Lake Success is in the Town of North Hempstead on northwest Long Island. Lake Success was the temporary home of the United Nations from 1946 to 1951, occupying the headquarters of the Sperry Gyroscope Company on Marcus Avenue. In 1939 the United States government bought a large tract between Marcus Avenue, Lakeville Road and Union Turnpike, to be the home to the Sperry Gyroscope Company which built a variety of maritime, military, aerospace and navigation products. During World War II the plant had 22,000 employees. After the war, part of the plant became the temporary headquarters of the United Nations while its headquarters building in New York City was being built. It borders the New York City borough of Queens. This Real Photo postcard displaying member nation flags, mailed in 1952, shows the building in which Security Council, Economic & Social Council and Trusteeship Council meetings were held. The card is in good condition, but shows some franking on the image, edge wear, and there appears to be some paint drops on the card's left side. The card has also lost its stamp. Official United Nations Photo (Department of Public Information).