Taris is a planet in the Force Galaxy dominated by one massive city, rather like another planet nobody cares about. The city grew and prospered but, as it grew, its population became increasingly xenophobic and soon the Human majority on the planet took over and made life very difficult for any non-Humans who lived there, even Humanoids. Centuries before the Reformation of the League, the Sith Lord Darth Malak razed the surface of the planet using the weapons on the Leviathan in his hunt for Rarth Devan. The city was rebuilt over time but it never really returned to its former glory, and even after the Reformation of the League certain massive areas of the planet remained destroyed, the gutted metal skyscrapers slowly being reclaimed by nature.
Taris was known for its strict caste system - if you were rich, you lived in the overcity. If you were poor, you lived in the undercity. If you were neither, you lived in between.