From Tekkenpedia

Acid Rain
Walls	Yes
BG Music	Street Wise and Street Wise (Asura Mix)

Acid Rain is a stage in Tekken 5. This stage is located in Seoul, South Korea (note the sign written in Hangul). Old buildings and a metal fence surround the fighters. There is also a little bit of rain falling into this area. A huge animated robot lobster is on the side of one of the buildings, higher up. This stage is the only stage with two songs which changes depending on the mode (Story Mode fights have Street Wise. Others have Streets).

The characters who have interludes in this stage: Lei Wulong and Feng Wei.