Cities: Skylines is a city-building game developed by Colossal Order and published by Paradox Interactive. The game is a simulation of a one-year open construction project. Players participate in urban planning by controlling zoning, road layout, taxation, public services and public transportation of the area. Players work to maintain various elements of the city, including its budget, health, employment and pollution levels. Players can also maintain the city in sandbox mode, which gives the player unlimited creative freedom.