Source: Wikipedia, "Imperium Romanum (video game)", available under the CC-BY-SA License.
Imperium Romanum is a sequel to a game by the same developer, Glory of the Roman Empire. Imperium Romanum features significantly improved graphics than its predecessor, and also adds some big Roman monuments such as the Circus Maximus and the Colosseum. The game doesn't necessarily have a 'campaign' mode like some other city-building games, but instead has the player play through different scenarios such as life in the chaos of Pompeii under the terror of Mount Vesuvius. Along with maintaining cities, the players must also keep them very well-organized and keep money spread out among the people. If there are cases of extreme poverty, then the people of the city may turn to lives of crime, which has a number of negative effects on the city.
The game features full 3D structures and people, and allow the player to zoom in and out of the scene as well as rotate the camera around a full 360 degrees. While much of the game is focused on building and maintaining cities, there are some RTS elements when opposing cities and civilization do battle with the player's. Along with building fortified walls and towers around the cities to prevent enemy attacks, players may also build objects such as trebuchets to go on the offensive against opposing nations.