Can you solve this riddle Elon Musk asks job applicants?

In the biography Elon Musk: Tesla, SpaceX, and the Quest for a Fantastic Future, author Ashlee Vance reveals a riddle that Musk reportedly poses to job applicants at SpaceX:

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?"

There are actually two correct answers.

For the answer, watch MindYourDecisions' Presh Talwalkar's video below.

(via Popular Mechanics)