Issued in 1923, this elegant 1 centimo stamp from Costa Rica commemorates the Universal Postal Union (UPU). Printed by the American Bank Note Company, it features the National Monument (“Monumento Nacional”) in San José — a patriotic sculpture celebrating the unity and defense of Central America during the 1856 campaign against filibusters. Rendered in a rich violet hue, the design showcases fine engraving and ornate borders typical of early 20th-century Costa Rican classics, making it a prized addition for collectors of Latin American and UPU commemoratives.