Then, the modern era allows you to developp aviation and tanks. In the Renaissance you will be allow to use gunpowder. For example, the units change with the times. Ten eras are Prehistory, Antiquity, the Middle Ages, the Renaissance, the industrial era, World War One, World War Two, the Modern Era, the the Nano Era and Space Era. The player changes era in garnering a number of resources and launching the search for the next era in one of its capitols.

In other words, you play as a nation which evolves over the periods. This map looks like the original game : Empire Earth.