As of 2014, the tallest man in the world is 8 foot 3 inches tall, according to the Guinness Book of World Records. His name is Sultan Kosen of Ankara, Turkey. As with many extremely tall individuals, Kosen's extraordinary growth is the result of a tumor on the pituitary gland.
Defects in the pituitary gland can lead to an over-production of the human growth hormone, resulting in gigantism. In 2010, Kosen began receiving treatments for his pituitary tumor, which, along with medications to control excess levels of growth hormone, was successful in halting his growth. The record for the tallest man to live on record belongs to Robert Wadlow, who was measured at just over 8 foot 11 inches tall. Wadlow died in 1940 at the age of 22.