There are several special corners in the land of Hyrule where Link can't run up unless you set him up correctly (the easiest place would be next to the boulder near the Castle). Run Link into the corner until his walk becomes slow and he doesn't go anywhere, as usual. Then press C-Up and point him so that the corner line is in the center of the screen. Now hit A and begin to run forward. Link will run up the corner and can run around on top. Be careful, not all of the ground is walkable (you'll know what I mean when you begin to fall into nothingness).
Corners and results:
A. As a child to the left of the Great Fairy's fountain entrance at Hyrule Castle. You are able to get inside the castle by going along the edge of the hills towards the back off it then jumping behind it, it's full of water. You can also get to the end of the road that leads towards the market, you can also jump off into the void.
B. On Death Mountain Trail, on the path that leads up towards the crater there is a hole with a cow in it, to the right of this hole is a drop off to the ground below, follow this drop off until it ends and a walls starts, right on the edge, the edge of this wall is the seam.
You can climb Death Mountain the hard way, up the side of it, beware of rock faces that are not solid, slide you to your doom or instantly kill you. To get to the top of the Mountain you have to go up a rock face right on the edge of the actual trail that looks too sheer to climb. It takes you into Biggoron.
C. On Death Mountain Trail, as you exit Goron City there is a drop off with a fence to the left, follow this drop off until it ends in a rock wall, the edge of this rock wall is the seam.
You can get onto a previously inaccessible bit of rock, you can also jump off into the void or onto the start of the trail below.
D. On Death Mountain Trail as you exit Goron City follow the wall to your right, where this wall turns further to the right is the seam, the corner of the turn.
Absolutely pointless, the top of the seam goes straight into the overhead rock, so it takes you nowhere.
E. In Gerudo Valley on the side furthest from the Gerudo's Fortress. The edge of the wall, that is on the right side while facing towards Gerudo Fortress, is the seam. The edge of wall on the edge of the cliff.
Almost impossible to climb, if you could climb it with the nearby cucco in hand as a child, you could float over to the other side and get into GF as a child.
F. In Hyrule Field, the corner of the raised area outside the Gerudo Valley entrance, the corner furthest away from the large tree that you see the owl in as a child.
Pointless, takes you to the top of the raised area, somewhere you can already go.
G. As an adult, when you enter the area outside Ganon's Tower from the market, it is the first corner to your right.
Although not half as hard as 'E', this is a devilishly tricky seam, when you get to the top you fall straight into the void.
H. As an adult in the area outside Ganon's Tower, go to the edge of the cliff that falls away into the lava and follow it towards the entrance to the Great Fairy's Fountain. Where it ends is the start of the seam.
Also extremely hard, I have not yet successfully climbed this seam, but I guess that when you do you'll simply fall into the void.
I. In the Gerudo's Archery Range, the corner directly to the right as you enter, many other corners can be climbed in here too.
Gives you limited access to the cliffs around the Archery Range, you can also jump into the void.
J. The entrance doorway to the Shadow Temple has two large angled pillars on either side of it, the corners of these furthest away from the door came be climbed.
You can get on top of the pillars.