In The World Meaning

(idiomatic) Expletive used for emphasis, for example after an interrogative word.

Example:   What in the world was that?
  Who in the world would want to do that?
2012 April 29, Nathan Rabin, “TV: Review: THE SIMPSONS (CLASSIC): “Treehouse of Horror III” (season 4, episode 5; originally aired 10/29/1992)”[1]:
  Writing a “Treehouse Of Horror”segment has to be both exhilarating and daunting. It’s exhilarating because it affords writers all the freedom in the world.
1900, L. Frank Baum , The Wonderful Wizard of Oz Chapter 24
  "My darling child!" she cried, folding the little girl in her arms and covering her face with kisses. "Where in the world did you come from?"