I still kind of like the idea of a man-made landmark possibly trumping a natural one. There are some amazing examples; apart from the ones I gave, you have the Statue of Liberty, Big Ben, The Brandenburg Gate, La Sagrada Familia, Stonehenge as mentioned (or was that built by aliens?) and The Sphinx to mention but a few. I'd like to see how they do against this guy God and what he can do. Might be fun.
Alternatively, if that doesn't suit, we could run a turn-on/turn-off thing, with one turn being man-made versus man-made, the next being natural vs natural and so on?
But I'm still for taking the Big Guy on, to be honest...
(Trollheart nervously checks the clear blue sky for thunderbolts...)