Thought I'd share some interesting notes in my collection. They are from the German invasion of Yugoslavia. In 1941, German, Hungarian and Italian forces invaded Yugoslavia. They managed to seize control of the Serb region of the country. Initial currency from this invasion were overprints of Yugoslav notes, I have one of two of these overprinted issues.
1000 Dinar 1941 - Serbia P-24 - Overprint of an unissued Yugoslav 500 Dinar 1939


These overprints were followed by occupational government issues.
500 Dinar 1941 - Serbia P-27b


The large white octagon has a watermark picture of Alexander I, a former King of Yugoslavia.
1000 Dinar 1942 - Serbia P-32


The large white circle has a watermark picture of Peter II, the King of Yugoslavia at the time.
500 Dinar 1942 - Serbia P-31


The large white circle has a watermark picture of Alexander I (mentioned earlier).
All the notes feature classic Socialist imagery such as industry, tools, livestock and the working-class man. Pay close attention to the intricate borders of the notes. Serbia remained an independent entity under German rule until 1943, when it and Yugoslavia were reunified.
But the most interesting thing about these notes, at least to me is that I did not buy them from a dealer. These were passed down to me by my great grandparents who were living in the occupied territory and were witness to the invasion and occupation of Serbia.