|Sid Meier's Alpha Centauri||
The true sequel to Civilization, Sid Meier's Alpha Centauri continues the story of the first colony ship sent from Earth. Choose one of seven factions to play, and struggle for control
An expansion called Alien Crossfire was released for Alpha Centauri, which offers another seven factions to play as, more technologies, units, etc.
Although SMAC was ported to Linux by Loki Games in 2000, that port is very difficult to find and is no longer maintained.