WORLD STAMP EXPO '89, the first international stamp show ever directly sponsored by the United States Postal Service, received its own commemorative stamp on March 16, 1989. The dedication ceremony was held in New York City, kicking- off the INTERPEX philatelic exhibition and the annual meeting of the American Stamp Dealers Association.
The new commemorative stamp incorporated a stamp-on-stamp motif that featured a slightly smaller reproduction of the classic 90-cent Lincoln stamp issued originally in 1869.
WORLD STAMP EXPO '89, staged in conjunction with the twentieth Universal Postal Congress, was scheduled for November 17-20 and November 24-December 3, 1989, at the Convention Center in Washington, DC. In order to consider and revise existing international postal regulations, the Congress, governing body of the Universal Postal Union (UPU), meets every four years. Results of the Congress dictate how member countries will process and charge for foreign mailing during the next four years. In 1989, the United States hosted the congress for the first time since 1897.
Designed by veteran stamp artist Richard Sheaff, the stamps were printed in the offset/intaglio process by the Bureau of Engraving and Printing.
Postal Bulletin (February 9, 1989).
Universal Postal Union. "What is the importance of the Universal Postal Congress?" http://www.upu.int/faq/en/upu_bodies/what_is_the_importance_of_the_universal_postal_congress.html.