Freeciv is a Free and Open Source empire-building strategy game inspired by the history of human civilization. The game commences in prehistory and your mission is to lead your tribe from the stone age to the space age.
Freeciv is a free turn-based multiplayer strategy game, in which each player becomes the leader of a civilization, fighting to obtain the ultimate goal: "To become the greatest civilization".
Players of the Civilization series by Microprose should feel at home, since one aim of Freeciv is to have optional modes (called rulesets) with compatible rules.
That also means it has very extensive multilanguage support, something rare in games.