Anime: Heavy Gear
Heavy Gear begins on a distant, fictional planet called Terra Nova around 4,000 Earth Standard Years from now (6132 AD). Terra Nova was once the crown jewel of the United Earth Governments colonies, however, an economic collapse forced the Terran government to abandon Terra Nova and all its other colonies centuries before the period depicted in the game setting, leaving Terra Nova in a dark age. Eventually, City-States rose from the ashes and either through treaties or tyranny, united to form national unions called Leagues.
These Leagues would in turn ally (again either peacefully or forcibly) to form the superpower blocs that dominated the temperate southern and northern hemispheres of the planet.