This long article describes some people who explore the many levels of sewers, tunnels, and hidden places under Moscow. Perhaps as many as 15 levels and maybe 500 or more meters deep. Show this article to anyone who says the dungeons often explored in Dungeons & Dragons are unrealistic or even impossible.
Here's a description of some exploration from late in article:
It's late afternoon now, and we're seriously lost, somewhere deep under a part of town known as Sukharevskaya, several levels below Moscow's Garden Ring speedway. We're making our way through a cool brick corridor strung crazily with dripping electric wires, wading through a foot-deep swirl of sour-smelling chemicals. Two flashlights have already died on us, and now there's only Mikhailov's headlamp, with its nice fresh batteries, to guide us to the surface.This sounds a lot like some fantasy dungeon expeditions my characters have been on. You can read the entire article here: FEAR ME, Giant Sewer Rodents, for I Am VADIM, Lord of The Underground!
We stumble across a threshold and the brick corridor opens up into a series of chambers. We've wandered into some sort of extensive hippie hideaway, room after musty room painted with sad, groovy murals: red guitars dancing with musical notes, rainbows, "Peace," "I Love the Beatles."
"These date back to the sixties," Mikhailov whispers reverently, as if we've just stumbled upon some priceless eastern adjunct to the Lascaux cave paintings. But then the sad-sweet hippie atmospherics darken. Charcoaled on a gray, square building support, Mikhailov spots some demonic, if misspelled, graffiti scrawled in English — "satin was here" and "666" — and instantly falls into a deep panic. "Devil-worshipers!" he says. "Shhh! Be still!"
We hear some indistinct droning above. Mikhailov is certain it's satanic chanting, that there's a coven just above us engaged in some sickening rite. He's breathing uneasily, hunting desperately for a way out before warlocks descend, his Russian Orthodox imagination running wild. He brandishes a knife, and we retrace our steps, past an old white stone chimney and central heating system. A shabby-looking elevator looms up from the black depths.