Space Vehicles

A glimpse at several potential mail delivery methods of the future is the theme of these four stamps issued by the U.S. in commemoration of the convening of the 20th Universal Postal Congress in Washington, D.C. from November 13 through December 14, 1989. The United States, as host nation to the Congress for the first time in 92 years, welcomed more than 1,000 delegates from most of the member nations of the Universal Postal Union to the major international event.