Hello how may I help you? Can you tell me who the tallest person in the world is? Sure do you mean the tallest living person or the tallest person of all time? Can you tell me who the tallest person of all time was? The tallest person who ever lived was Robert Wadlow who was born in Illinois and was an astonishing 8 ft 11 inches tall! Would you like some more information on Robert Wadlow? Sure. Tell me where Mr. Wadlow was from Robert Pershing Wadlow was born in Alton, Illinois (USA) on February 22, 1918. He had a medical condition [ . . . ] What type of medical condition? relating to a pituitary tumor (hormones) which led to his extreme growth! How sad. Thanks for all the interesting information. Sure you are very welcome.