Cities: Skylines is a 2015 city-building game developed by Colossal Order and published by Paradox Interactive. The game is a single-player open-ended city-building simulation. Players engage in urban planning by controlling zoning road placement taxation public services and public transportation of an area. They also work to manage various elements of the city including its budget health employment traffic and pollution levels. It is also possible to maintain a city in a sandbox mode which provides more creative freedom for the player.