Camp Upton was one of 16 cantonments built to train soldiers quickly upon the United States' entry into World War I in 1917. The camp was located on nearly 20,000 acres of scrub pine forest on the eastern end of Long Island, New York. Later, it was a Civilian Conservation Corps camp and was rebuilt for use in World War II. It is now the site of Brookhaven National Laboratory. It was the home of the 77th "Liberty" Division, whose soldiers, many from the New York area, distinguished themselves in battle in the Argonne Forest in France near the end of the war. Its most famous soldier, Irving Berlin, wrote "God Bless America" and Yip Yip Yaphank, a "military mess," while training there.