[Douchetallica]

The fine detail on the destroyed walls (front right side) has fragments sticking out, would be an insane amount of work to do and a resource hog when lighting. Ergo, that whole structure is a static mesh.

The building on the front left... first floor wall is a BSP brush as well as the second level floor. The second floor walls are static meshes because of the complex design.

The building on the far back left... could be entirely BSP brushes since it's simple... but the railing and support columns are more than likely static mesh.

The church... the walls might be BSP brushes but I doubt it. I say the entire thing is a static mesh. Easiest and fastest way to do it is in Maya.

Ergo, I believe 90% of the stuff in the screen shot is a static mesh aside from the backdrop and terrain.