Lost City (Diablo II)
The Lost City is the fourth desert area in Act II, but unlike the previous areas it is filled with destroyed buildings. When the player first enters this region, The Tainted Sun quest starts after 15 seconds, darkening the overworld into a night darker than normally. To remove this the player must complete said quest.
The Ancient Tunnels lie in this region, which appears to have been the sewer system of whatever town lay here before.