A Spanish Galleon ship called the Tortugas was carrying cargo from the New World to Spain in 1622 when it was hit by a hurricane and capsized, losing its treasures to the sea. The Spanish Reales (also known as Pieces of Eight) were used as Spanish currency for centuries and were designed to weigh one ounce. The fine silver coins are irregularly-shaped as they were chipped off by hand to try to hit the exact desired weight.
