Fallout 3: The Pitt
Upon starting Fallout 3 with The Pitt installed, the player will receive a radio message from an escaped slave. The slave will encourage the player to leave the Capital Wasteland by rail and head up to The Pitt, with the hopes that the player will free more slaves from a crippling mutation sweeping through their settlement. The player must pose as a slave themselves to gain access to the city, after which they may roam freely around the city's districts (a contrast to the linear nature of the previous DLC, Operation Anchorage) and choose which faction to side with.
Aside from the new locations, The Pitt offers five new quests, three new perks, and four new achievements. New items can also be found, most notably a series of powered melee weapons based on industrial cutting tools.