I have this sort of pin I guess made of three coins. I know the two outer coins are 5 Kopeck coins from 1905 and 1911, but the center coin, or medal or whatever it is appears to be German, with an Iron cross on it, from 1915, with the words WELT-KRIEG on it. Can't find this coin anywhere. And is there any significance to these three coins being combined to create such a pin?