UPU - Universal Postal Union old postcards, depicting world's coins of different national currencies. Each card shows the country's coinage, embossed on the card, as well as the country's flag ( most of the cards). The original publisher of the H.S.M. type of cambist cards was Hugo Semmler of Magdeburg. These postcards were printed in early 20th century (around 1900s. and 1910s ). Some earlier versions of these postcards do not show currency exchange rates in the middle of the card. Later versions of these postcards from around 1920s are published by other different publishers and don't have H.S.M. initials.