A rock carving with depictions of money: strings of coins, but also the jiaozi bank notes from the Song dynasty- i.e. the oldest paper money. It was found in Chongqing (a location where iron currency was also used during the Song). Watch this short video to learn more: Stone Carving of World's Earliest Banknote "Jiaozi" Discovered in Southwest China
More photos on this web page (text in Chinese).