There are 3 walls?
HOLY SHIT FULL OPENING
as i recall, this is the shittiest wall.
Also: wouldn't it be much, much safer to go underground, Gurren-Lagann style than just build some walls? I mean, sunshine's nice, but not worth it when there's giant naked people running around about to eat you.
it's actually kind of difficult to go underground y'know. I mean GL managed it because they had all these mechs and advanced tech around and Genome wanted it to occur