Is there any information on the fall of Mountain Glenn in any sources beyond the show? I ask because, poorly designed* as the defensive wall appears to be, I can't see how the forces of Grimm managed to take the city.

Also, is there any information on why the subway system between Mountain Glenn and Vale comes out above ground in Vale? I'd have thought they would have tied it in with the existing subway system, or at least kept it below ground to make construction easier.

• I fully accept that most defences in popular media are going to be mediocre at best due to writers and artists not being particularly informed about the evolution of fortifications, but I reserve the right to hitch when they're particularly bad (Attack on Titan, I'm looking at you).

Edit: Thanks everyone who answered me. I really appreciate the time you put into your posts and the lack of mass downvotes that you see in some fandoms.