Commerce is the exchange of goods and cash between communities within and around a city, the exchange of knowledge and ideas, travel and shopping. It is the commercial exploitation of goods and services within your society. Commerce production depends upon the terrain within the city's radius, because citizens laboring there produce commerce. When the City Display is open, you can see what the citizens are producing. A citizen working Produces Floodplains 1 2 with road. Grasslands 0 1 with road. Plains 0 1 with road. Hills 0 1 with road. Mountains 0 1 with road. Forests 0 1 with road. Jungles 0 1 with road. Marsh 0 1 with road. Note any square next to a river produces one extra commerce per turn, and some natural resources provide bonus commerce as well. The government derives Tax Revenue from commercial activity and divides the revenue into three areas, * The build-up of liquid wealth in the treasury, * Long-term investment in scientific research, or * The entertainment of the population to produce happy faces. The allocation of tax revenues into these three categories is set using the Revenue Slider on the Domestic Advisor.