Okay, I'm just going to start shamelessly plagiarizing Defender's titles, if he's going to post my bunkers before I get around to it, dammit

No seriously, thanks for planning this trip, it was pretty cool. We went here on a weekend morning as part of our initiative to get the fuck underground where it's no so cold.
Took me a bit longer to work on my pics and I'm not terribly happy with the lighting. As has been pointed out, this is pretty well photographed, probably mainly because of the old Peugeot 203 and the unidentified even older vehicle inside. Not sure if it's a Traction Avant, as the engine compartment looks a bit short.
According to one of my associates who researches such things, this was a munitions factory in World War II, moved underground into a limestone quarry outside a large German city to escape Allied bombing.
There's not much left of the industrial part, except for power and comms lines, metal-clad air ducts, broken water mains, and concrete bases for industrial equipment. Apologies for not including more details, but I was unable to find anything specific, even some of the guys
It's a nice-looking quarry, with some bizarre protective structures, probably left over from laser tag players, and not too much graffiti or trash. Also, a good opportunity to play with goofy lighting, not all of which came out to my satisfaction, partially because I can't figure out how to fix my %)(*@!) Photoshop colorspace to synchronize with Lightroom.
More, as always, at Kosmograd dot net.