The world’s tallest man is Sultan Kösen (Turkey, b.10 December 1982) who is 251 cm (8 ft 3 in). He also holds the records for widest hand span and largest feet on a living person. Sultan is a part-time farmer and has severe case of acromegaly, a long-term condition in which there is too much growth hormone and the body tissues get larger over time.
He Pingping (L) of China sits on the foot of Sultan Kosen of Turkey as they attend the Guiness World Records Live! Roadshow, on January 14, 2010 in Istanbul, Turkey. He, standing at 73 cm (2 feet 5 inch), and Kosen, at 246.5 cm (8 feet 1 inch), are both in the Guinness World Records for their diminutive and augmentative statures.
Before Sultan, the tallest living man was Xi Shun (China, b. 1951), measured 2.361 m (7 ft 8.95 in) from Mongolia. Check out this video about Xi’s visit to London: