Ponkotsu is a combination sandbox and post-apocalyptic Steampunk build. Many of the signs are in Japanese (some are in English), so I don't know whether there is a backstory to the place or the designers just liked the look, but the half-ruined buildings and rusting iron are interesting to wander through.
There's a floating laboratory:
And, of course, what self-respecting post-apocalyptic Japanese sim would lack an enormous monster?
One young lady was in the sim with me, an attractive lass with a Japanese avatar name and some odd tastes in both attire and settings. She wore a cropped tank top that was pulled up to expose her breasts (which had little "x" pasties on them), and a pair of ripped jeans that looked normal in front - but fully exposed both buttocks. (Hence no picture.) She had one of those annoying fidgety AOs, so she was in constant motion, which demonstrated that she had Avatar Physics turned on in Viewer 2, and the breast sliders slammed to the right. Every time she moved, her breasts jiggled; when she moved more than a few inches, the girls seemed like Slinky toys trying to escape. I was transfixed - it was like watching a car wreck.