This stamp commemorates the Sixth International Philatelic Exhibition (SIPEX) held in Washington, D.C., May 21-30. A souvenir sheet was also issued for the event.
1966 SIPEX 5c Multicolored
This stamp commemorates the Sixth International Philatelic Exhibition (SIPEX) held in Washington, D.C., May 21-30. A souvenir sheet was also issued for the event.