20 Lira Archimedes

Turkey has issued a series of silver coins honoring figures from the ancient world, and Archimedes — born in Syracuse, a Greek colony in Sicily, around 287 BC — fits squarely into that tradition of claiming broad Mediterranean heritage. His famous displacement principle reportedly came to him in a public bath in Syracuse, prompting an exit memorable enough to survive two millennia of retelling.

The 31.1g weight places this squarely in the one-troy-ounce bullion format, though Turkey markets it as a collector piece rather than a bullion vehicle.