500 Roubles, Russian Empire, series 1912

Peter I on the 500 is the empire quoting its own founding myth at the moment it was about to end. The note appeared in 1912, in the last stretch of confident peacetime finance, and it is the physical high-water mark of Russian banknote design: enormous, densely engraved, with a portrait watermark that still defeats casual reproduction.

Its size is also its curse as a collectable. At roughly 27 centimetres across, nobody carried one flat. Almost every surviving example was folded — often in halves and then quarters — and the fold lines are where the paper failed first.

During the Civil War these were among the "Romanov" notes that both sides tolerated and the public actively preferred, trading at a premium over Soviet and White paper alike. A note promising 500 gold roubles from a state that no longer existed was, for a while, better money than anything currently being issued.