What is the most expensive Spanish silver coin in history?
Can you tell me, what is the most expensive Spanish silver coin that has ever been sold? I'm curious to know if there's a particular coin that stands out as the most valuable among all the Spanish silver coins that have been traded and collected over the years. Is it a rare piece with a unique history, or perhaps one that's been in the possession of notable collectors? I'm eager to learn more about this fascinating aspect of numismatics.