New York City

On October 24, 1949, exactly four years after the United Nations Charter went into effect, the cornerstone of the permanent U.N. headquarters was laid in New York City. U.S. President Harry Truman attended the ceremony and gave a brief address in which he pledged continued American support for the U.N.'s mission to secure world peace, to further respect for human rights, and to encourage economic development in poorer nations. The headquarters was to be built on land donated by American industrialist John D. Rockefeller, Jr., along New York's East River. Designed by an international team of architects led by American Wallace K. Harrison, the U.N. complex consisted of three main buildings: the General Assembly building, the Conference building, and the thirty-nine-floor Secretariat building. The Dag Hammarskjold Library was added in 1961. The eighteen-acre site is an international zone belonging to all U.N. member states and includes its own security force, fire department, and postal administration.