I assume mad casualties. I also figure since they usually get destroyed in extraordinary ways, some construction company out there got the rebuilding tech. That's be a good indie film idea...The Rebuilders. Superheroes destroy the city and they clean it up. Could be funny lol.
Meh, I just assume the Cat-In-The-Hat shows up with his machine that cleans everything up like nothing ever happened. Gotta sleep at night.