Freeway overpasses, ever walked across one of thoes and looked down? I'm not scared of hights, I've been rock climbing without any fear of falling. I think it's the shear movement of mass.
Like the freeway, a long arch bridge, at the top: The drop would be incredible, and if there were passing ice chunks, you wouldn't know if you would hit one...
So cliff diving would be right out? I don't know, some how I think being able to see the bottom might be a tad bit worse when you combine the two, painful at the very least.
Déjà vu is another thing that tends to creap me out, expeicaly when it starts looping déjà vu of déjà vu. but that's not a place, so....
Awareness of swarms of things,
like when you see one small spider then you notice another and another
and suddenly you've got your eye in and you can see loads and loads
then you look down and there on you and in the air on webs and stuff
(actually happend like that in our poly tunnel)
Its a cheesy site, but I enjoy browsing theshadowlands.net's haunted places index, founding about all kinds of things near my own home. The index is even international in fact.
Yes, murky waters, even in places which you know for fact are shallow, can be quite disturbing for no apparent reason. However, I've dived in the harbour a few times. I wonder what the brain thinks under condition 1?