its the road part of ctf_doublecross, the trees are added props
you should be able to select a section called "tf2 maps" when you're starting a new game in garrys mod, it might not have a picture but the name'll be there
might be able to see it better here:
actually anyone know how i'd get a zebra crossing into this?
in the original photo john lennon had a cigarette but it has been photoshopped out of recent releases of the album/showings of the album artwork... work that into it? Wouldn't shopping the lines in be easier than say, getting the map into hammer and putting them in that way?