The 40th anniversary of the discovery of radium by Marie and Pierre Curie was commemorated in France in 1938 with the release of a semi-postal stamp bearing a 50-cent surtax to benefit the International Union Against Cancer (UICC). The French Postal Service expected member countries of the Universal Postal Union (UPU) to prepare a similar stamp, but only Monaco and Cuba did so. Due to the lack of response, France issued stamps for 21 of its colonies, with each stamp having an identical design except for the name of the colony.
Pierre Curie (1859–1906) and Marie Skłodowska–Curie (1867–1934), discovered radium (Ra) on 21 December 1898 in a uraninite (pitchblende) sample from Jáchymov (in the Czech Republic)
Omnibus design by French painter Joseph de la Nézière (1873–1944), engraving by Jules Piel (1882–1978)
