Middle Ages, Renaissance, Imperial Age, Enlightenment Age, Industrial Age, Modern Age, Atomic Age, Digital Age, Genetic Age, Synthetic Age. Before buildings and units can be made or created, resources must be gathered. There are two kinds of resources: the main resources and special resources. The main resources are available in all epochs and they are food, wood, gold, and stone. To collect resources, a citizen (or a band of citizens) is selected, and are directed to a resource. The citizens thus begin harvesting it. The special resources are available in only some epochs. These special resources are tin—available until epoch 6, iron—first available in epoch 4 and is no longer used after epoch 9, saltpeter—first available in epoch 7 and is used until epoch 12, oil—first available in epoch 10, and uranium—first available epoch 13. Empire Earth II has technologies to improve each player's civilization. Technologies are divided into three groups. The first is Military, which provides benefits mostly to military units. The next is Economic technologies, which increases resource gathering rate, decreases cost and building time for units and buildings and decreases tribute tax amount. The final group is Imperial, which provides benefits mostly to special units and increases the health of units and buildings. There are four technologies of each group for each epoch. Technologies can be researched by spending tech points. To get tech points, an appropriate number of citizens must be garrisoned in a university and/or an appropriate number of priests must be garrisoned in a temple. Technologies are researched through the main interface (no longer through a building) by clicking the Technology Tree button. When the correct number of tech points are available, the tech tree button will light up and new technology to research can be chosen. However, when research is no longer used (at the highest epoch specified before starting a game), the garrisoned units will become idle. In Empire Earth II, each civilization belongs to a particular world region, each having its own regional powers. These can be activated on the game interface by clicking on a crown in the top right corner. All of the regional powers are timed; once the time is up to use it, it takes a long time for the regional powers to be recharged to use again. Each regional power can only be used in a respective group of epochs. For example, the regional power of