I went through my Guild Wars screenshot folder and picked out a few. Unfortunately there are people in a couple shots, but if you like the shot enough maybe you could crop them out or something!
Riding inside worms in the desert:
Fighting the dragon Glint:
This is a shot inside the KING guild hall
In a dungeon with the silhouette of a robot in the background
I never figured out why this castle was floating
I'm not aware of any walls in Guild Wars, unless you count the Great Northern Wall, which the Charr broke. I bet if someone ran around Ascalon City in presearing (the training area when you start a new character) they could get a few shots of it.