"Dungeons are concerningly convenient in a lot of respects and I do not know why and it bugs the heck out of me."

"Are there theories?"

"Nothing very compelling. Espers and dungeons appearing at the same time makes me think we're connected somehow, but 'connected somehow' isn't a theory."

"When was that again?" It was mentioned in the article but Lucien got distracted quickly by the industrial applications pages.

"Seventies. It was a mess, nobody knew how anything worked, a lot of big name dungeons that recur all the time were ones that got away back then, we didn't know about guiding right away..."

"That sounds like it would make for a... very chaotic time."

"It was not immediately clear that we weren't looking at the apocalypse, apparently, but we pulled through and most economic models think that dungeon material exploitation is doing the economy favors. Also cuts down on foreign adventurism and distracts your run of the mill warlord some; anyone who has a competent combat force has lots of reason to put it toward clearing dungeons."

"What sort of material exploitation?"

"Dungeons contain stuff! Most of the stuff is boring but sometimes a monster part or a landscape feature will turn out to have cool magical or material properties, some of which can even be reverse-engineered. Have you read enough Wikipedia to know why superconductors are exciting?"

"No, why are they exciting?"

"They're important for electrical engineering reasons and some have been reverse-engineered from dungeon materials, it's the standard example. There's also batteries that can store some kinds of esper powers, and this frictionless stuff that hasn't been reverse-engineered yet but the dungeon that produces it is recurring so every time it pops up somewhere people harvest a lot of it while the rescues are ongoing. And there's Cricket, who came from a four-dimensional dungeon and has changed some since then but can still navigate in four dimensions, so he's useful in other 4D ones."

"Huh, does reverse-engineerability imply they were themselves manufactured technology? Also how do four dimensional dungeons work?"

"We have no idea how dungeons do things, but apparently 'time travel' is a possible factor. I do think they have to be drawing on human concepts somehow."

"Why?"

"They'll produce dragons, which never otherwise existed, and winged cats, and zombies, and lava elementals, and yetis. They don't do anywhere near as much creature- and concept-remixing that isn't of a kind that would be or has been interesting to a human, they're drawing on mythology and fantasy. Yes dinosaurs, which are very interesting to humans; not so much extinct fish that look to us mostly like extant fish. Rather few fish in general, most of the surface of Earth is water and almost every dungeon has breathable air."

"Is it possible there are dungeons that only open up underwater, so humanity just doesn't notice?"

"Dungeons like cities. They will appear in smaller towns sometimes but not even on, like, a farm, let alone the ocean. I've heard of one spawning on a cruise ship though."

"... Huh, that is really weird. Did the cruise ship one move with the cruise ship?"

"Yup."

"They really don't sound like a natural phenomenon."

"As in you think they're artificial or what?"

"I guess I must? It just doesn't sound like you'd get that behavior if they weren't created by some sort of intelligence."

"Yeah, one hypothesis I sometimes toss around is that there's aliens involved."

"...are those known to exist?"

"Nope."