OpenCity is a free and open-source software 3D city-building game started in 2003 by France-based Vietnamese programmer Duong-Khang Nguyen.

In the game, the player builds a city by marking land as commercial, industrial or residential zones.

The player is also required to supply the city with power and connect the different zones by building roads.

OpenCity is the product of programmer Duong-Khang Nguyen and 3D artist Frédéric Rodrigo.

[11] OpenCity has also been packaged for many Linux distributions: Fedora,[8] Debian,[9] SuSE, Slackware, Ubuntu,[7] Pardus, Frugalware.