For our archeology and history enthusiasts: Okinawa was a historical trade hub, and recently ten ancient coins, including several from the Roman and Ottoman empires, were excavated in Katsuren Castle, Uruma, Okinawa.

Image of a 4th century coin with an outline of a portrait. Jiji Press/AFP/Getty Images

“We don’t think that there is a direct link between the Roman empire and Katsuren castle, but the discovery confirms how this region had trade relations with the rest of Asia,” Yokou, told CNN.

Read more on CNN (the most detailed), NPR, and The Japan Times.