Located in the Ojoster Sector of the Outer Rim Territories, Taris was an ecumenopolis founded at the nexus of several hyperspace trading routes. Prosperity led to a rapid population increase and the continued vertical expansion of the planet-wide urban sprawl. But with the discovery of superior trade lanes elsewhere, Taris's economic fortunes changed.
For the wealthy nobles living in the upper floors of the towering skyscrapers, Taris remained an urban paradise. As one descended, however, the standard of living dropped precipitously. Aliens and refugees were forced to live in the city's lower levels, supporting the upper classes both figuratively and literally. Near the surface, violent swoop gangs held sway over a terrified civilian populace beset by poverty and famine, and the sewers of the undercity were infested with rakghouls.
Ironically, many of those living in the lowest levels of Taris survived Darth Malak's bombardment, while the rich and powerful were almost entirely wiped out.