I'm a simple emigrant, and I'm in shock

There's a big park not far from me, and we go there to walk there very often. And every time we pass by there, I can't take my eyes off one building that's in the photo. First, it's simply scary because it's abandoned in the middle of cute, beautiful houses; second, what are these doors with peepholes in the windows, and anyway, what size are these windows? My wild imagination immediately pictures: “what if someone has been kidnapped and is being kept there on a chain right now.” And considering Germany's history, there are countless options for using creepy buildings. I've already asked a bunch of German friends and googled, but the mystery of the abandoned house remained shrouded in gloom. Now I was collecting material for something else and came across a photo of this very building, surrounded by others like it. Do you already have any guesses what it is? I won't keep you in suspense: it's a bunker! And in Frankfurt there are at least 23 more of them. Some bunkers have been converted and are now used as a warehouse, a bar, and even a kindergarten, but most remain abandoned. Such an unusual system of above-ground bunkers may have saved peaceful residents during carpet bombings. It's not unlikely that, thanks to these shelters, the mortality rate from bombings during World War II in Frankfurt was only 1%, whereas in other German cities it was several times higher. For example, Berlin 2.5%; Cologne 3.5%; Darmstadt 10.9%; Dresden not less than 12%. The truth turned out not to be pleasant either, but it's better this way than if I kept coming up with more options. Check out in the comments the map of Frankfurt's above-ground bunkers. #frankfurt #history