Elon Musk's famous interview question

When Elon Musk interviews someone for a job at Tesla or SpaceX, he'll probably ask you: "You're 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?"

Most people correctly state the North Pole, But then Musk will ask where else it could be. Few can find another possibility, which is somewhere close to the South Pole, where, if you walk one mile south, the circumference of the Earth becomes one mile.