Near the German border of Switzerland, every railroad and highway tunnel has been prepared to pinch shut explosively. Nearby mountains have been made so porous that whole divisions can fit inside them. There are weapons and soldiers under barns. There are cannons inside pretty houses. Where Swiss highways happen to run on narrow ground between the edges of lakes and to the bottoms of cliffs, man-made rockslides are ready to slide.

When I lived in Switzerland you'd see houses that looked like people lived in them, but inside was anti-aircraft machinery... Trick or treat anyone?

I like the idea of terrain as a weapon.