20 Cent Chateau de Vianden

Vianden Castle, perched above the Our River in northeastern Luxembourg, was allowed to fall into near-total ruin after the Nassau family sold it to a private speculator in 1820, who promptly stripped it for building materials. The Luxembourg state eventually repurchased the remains and began a restoration project in the 1970s that continued for decades — making it one of the more protracted castle rehabilitations in modern European history.

The selective rhodium plating on this issue is a production choice worth noting: rhodium, a platinum-group metal, trades at multiples above gold and is applied here in microscopic quantities purely for contrast, not bullion value.