It you thought Mos Eisley was a wretched hive of scum and villainy, wait until you get a load of Belsavis, the Republic prison planet that houses some of the most fearsome criminals in the Star Wars: The Old Republic galaxy.
The use of Belsavis as a prison planet actually pre-dates the Republic. The good guys of The Old Republic stumbled upon the Rakatan Empire-constructed facility while exploring the planet's surface 50 years prior to the events in the game, and decided that it was probably best that someone maintain the force fields, lest ancient evils be unleashed.
So the Republic started adding their own prisoners to the prison, which by the time you start playing the game is positively bursting at the seams. Sounds like an amazing location for some sort of raid event, doesn't it?
Find out more about Belsavis at the Star Wars: The Old Republic Holonet page.