World maps can be traded in diplomacy.
Maps provide a diagrammatic representation of an area, showing terrain features, cities, and other landmarks. The earliest maps were etched clay tablets charting Babylonian lands for the purposes of taxation. Around the same time, the Chinese produced regional maps drawn on silk cloth. In between 600 and 200 BC, the Greeks produced several maps of the known world, including the first map showing a primitive system of latitude and longitude. Traders and merchants primarily used these early maps. Seamen, who often set their courses based only on the tales brought back by previous voyagers, benefited most from the science of map making.