The image is a photograph of a plaque on a wall that reads "The first coins: The rapid growth of trade during the 7th and 6th c. BC made pressing the need for standard mediums of exchange. In earlier periods, traders used various devices for measuring and exchange, such as ingots, rectangular slabs, and spits, to produce the first metal coins of the year. The first metal coin is made of steel and has a diameter of approximately 1.5 inches. The second metal coin has a length of approximately 2 inches and a weight of approximately 3 inches. It is also made of silver and is a symbol of the city of Athens, Greece. The third metal coin also has an inscription that reads, "In addition to their economic significance, coins also had a political dimension they served as emblems of the various cities on the international markets. Coinage is the first state of the United States of America, as an autonomous political institution by the first decades of the 6th century BC."