and what's helix canyon's "direction"?

2 oposing bases, in a boxed in area, with 2 areas you can walk/drive up and a cave in between, that you can fall into but not come out of except for the middle where 1 side path goes down into a cave and where the other side path goes up to a wall with a clear view of both bases.

I see something with path's to walk on on the sides, but I don't see how 1 could go up and the other down in a structure like that.