You are standing on the surface of the Earth. You walk one mile south, one mile west, and one mile north. You end up exactly where you started. Where are you?

"Well, for this to make sense, since there are only three moves involved here, the geometrical shape of the route taken cannot possibly be a square, right? To take three moves and end up where I started, the shape would have to be a triangle. For that to be the case, where on Earth would I have to be if I were to end up where I started in three moves like that? It would have to be a fixed point on the planet. The planet is spherical, but if I walk one mile south, then one mile west, and then one mile north, those are fixed directions that cannot be altered. That would mean it was a direction that is fixed, such as The North Pole."