I don't know for sure if it is allowed here because it is not really a coin but more of a commemoration "token" for the Royal Dutch Row & Sailing Society. I haven't found much information yet but it's likely fairly rare if not beautifull.. I think this is a nice place to share it
Here's another non-coin, but it is often collected alongside the coins of the classic-era US commemorative coins - the octagonal 1925 Norse-American medal. The piece features a circa 1000 Viking longship on its reverse.