Английский словарь американских идиом - in the world

or on earth {adv. phr.}, {informal} Of all possible things; ever. - Usually used for emphasis after words that ask questions, as "who", "why", "what", etc. * /Where in the world did you find that necktie?/ * /The boys wondered how on earth the mouse got out of the cage./ * /Betty could not understand what on earth the teacher meant./