My thought for Numenera’s Ninth World setting was an automated ferry terminal from a previous civilisation, because I was inspired by the ‘Gateway’ novel by Frederick Pohl. Basically the idea is that you find an abandoned transport hub containing a number of pre-programmed ships/trains/shuttles/whatever you like, so that once you’ve explored and investigated the facility itself, you then have the option to potentially get in one of these vehicles, turn it on, and roll the dice that its pre-programmed route is going to bring you somewhere interesting and/or survivable. If its something like a rail or subway system, you also have the option of manually exploring the connected tunnels as well. A fun way to chain dungeons together, the first one linking out to others. Depending on the size of the vessels in the hub, like the ships in the ferry terminal example, or space ships if you found, say, an asteroid deployment base or something, they might also function as their own little mini-dungeons as well.
For science fiction in general, absolutely anything that’s been automated and then abandoned. Factories, supermarkets, theme parks, hospitals, literally anything. Because the thing with something that’s automated and running on remorseless, unchangeable programming, is that even if it’s the most harmless thing in the world, if you don’t know the procedures, then you’re stepping inside a massive operating machine with no knowledge of how to traverse it safely. Like, you’d think no one would make an automatic supermarket that would kill you, but then maybe they just never expected someone to try to use it without what they considered the absolute base-level know-how for someone in their society, such as, for example, the ability to read their language, or the knowledge that their tech is voice-activated, or the cultural understanding that payment comes first, or the ability to recognise the visual indicators for an emergency stop. Everyone’s had the experience of trying to navigate the most obstinate automated menu. That, but physical, and possibly in an alien language, and possibly arranged in such a way that if you push the wrong buttons, grievous bodily harm can result. Lots of modern industrial set-ups have ways to do hideous damage to you, because they assume that if you’re going to be operating outside its usual parameters that you know the procedures to turn things off to do so safely. But if you’re say, 200 years late to the party, don’t read the language, and possibly didn’t even know you were in a machine in the first place, well …
And that’s leaving aside the idea that the programming has decayed or run into other issues while operating for an extended amount of time unmanned. I’m not even talking about AI here, I’m talking about a machine that’s been running dry for 80 years because no one was putting materials in but no one turned it off either, and now its dangerously close to exploding and one wrong sneeze in its vicinity will do very bad things to a significant chunk of the surrounding landscape. The final boss of this dungeon is the dangerously overheating stationary behemoth on the lowest floor that the players have to disable without blowing the whole dungeon sky-high in the process.
