20th UPU Congress, Classic Mail Transportation

A review of historical methods of delivering the mail in the United States is the theme of these four stamps issued 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.