British Guiana1856 one cent sol for $900 000 in 1980

This 1856 one cent black on red stamp was once considered to be the world’s most expensive postage stamp. The stamp depicts a ship and also the latin motto of the colony which says “ we give and we seek in return”. Each of the issued stamps had their corners clipped as well as signed by the post office employees in order to prevent replicas.  In 1980 the stamp sold for around 900.000 USD.