Robert Pershing Wdlow (February 22, 1918 - July 15, 1940) is the tallest person in history for whom there is irrefutable evidence. Wadlow is sometimes known as the Alton Giant or Giant Illinois because he was born and grew up in Alton, Illinois.
Wadlow reached 8 ft 11.1 inches (2.72 m) in height and weighed 199 kg at his death at 22.His great size and his continued growth in adulthood were due to hyperplasia of his pituitary gland, which results in an abnormally high level of human growth hormone. He showed no indication of an end to his growth hormone. He showed no indication of an end to his growth even at the time of his death.