In the 2400s, mankind begins to terraform the planet Mars. Giant corporations, sponsored by the World Government on Earth, initiate huge projects to raise the temperature, the oxygen level and the ocean coverage until the environment is habitable. In Terraforming Mars you play one of those corporations and work together in the terraforming process, but compete in doing the best work, with victory points awarded not only for your contribution to the terraforming, but also for advancing human infrastructure throughout the solar systems and other commendable achievements.
The players acquire unique project cards, which represent anything from introducing plant life or animals, hurling asteroids at the surface, building cities, and establishing greenhouse gas industries to heat up the atmosphere. You compete for the best places for your city tiles, ocean tiles and greenery tiles. When the terraforming process is complete, the player corporation with the most victory points wins.