Yeah cool image alright but I don't think its real! Please prove me wrong but I cant find any similar images under Google Image search. Look at the blurring in the rocks and trees on the left side of the "Massif". The place dose exist, but this is an edited photo so it don't quite look like this, wish it did
However you could do this in Terrqagen but your issue will be getting the arch to work well, it may end up being a paint over job using a couple of renders.
Who's gona try it?
Richard