I've collected coins for a few decades, and this is the weirdest thing I've ever seen:

"Die Schwarze Schande", 1920 Rhineland occupation commemoration coin

It's a propaganda piece, and noteworthy that it precedes Hitler's rise by a decade. But as the listing cites, marks events referred to by Hitler in Mein Kampf.
The giant penis the woman is bound to, and the French-helmeted head, make me wonder how anyone could take the thing seriously. This is a commemorative coin, not one in circulation used as currency. The one I saw for sale was a later minted copy, not the original shown here.

One of the aspects I like with coins is the enlightenment they provide to historic events.
Of U.S. coins, I especially like the ones minted in the first half of the 20th century, particularly those listed in a section called "commemorative silver", commemorative 50-cent coins minted usually one year, mostly in the 1920's and 1930's, commemorating major events in U.S. and state history, such as the Oregon Trail, the 400th anniversary of Columbus discovering America, with some particularly nice designs. Their limited nature makes them sell for much higher than most coins.