Forward slope

[Bunkerfreak]

Perhaps also the reason why those corridors are so high, at the point where the inner steel plates of the roof are, its where the diagonal edge of the former outer wall begins, so they don't have to cut deep in the old bunker (which weakens the concrete's strenght ofcoarse) to get those steel bars in place, and therefore the presence of the "bump" above this high corridor...

I see it only now, when discussing this bunker, that's where fora's are good fore