As a child, the world’s tallest man was diagnosed with a pituitary tumor that caused his body to grow uncontrollably, leaving him with difficulty walking, not to mention fitting in.
Although the previous record holder, Ukrainian Leonid Stadnyk, reportedly measured 8 feet 5.5 inches (2.57 meters), Guinness said he was stripped of his title when he declined to let anyone confirm his height. For more info.

And a video: