The first one, with the mediterranean trees and vast flatland, I think is possibly Cannae, as it looks vast enough to have accomodated such armies.

The second one, could be Teutoburgerwald, considering the northern european trees, and it's a battle which location has been hotly contested for a while - though I saw on Terry Jones' "Barbarians" that they may be more certain about its location now after a British ex-Major and amateur-archaeologist found some Roman coins in a field.. the place has its own sign now as the battlesite.

But these two candidates have already been taken by Bonny