I've been doing some outside Gilneas starting zone explorations and found some stuff that's quite interesting. When you complete the gilneas quests you become phased a lot and with the phases the textures and houses for example change / get deleted.
Compare the maps (both pics are on the same spot but in different phases):
I moved on and noticed that there was a fortress in my phase which people in starting quest didn't see!(Not shadowfang keep, it was alot smaller.)(Unfortunally i don't have pictures from the starting quest phase.)
I could not reach to this one because of sticky walls + the land was not walkable/fell down under it and dc and teleport to graveyard, so i will let this be a challenge for you guys to complete!
If you get there, please let me know!