Robert Pershing Wadlow (February 22, 1918 – July 15, 1940) was the tallest person in history for whom there is irrefutable evidence. Wadlow is sometimes known as the Alton Giant or Giant of Illinois because of his upbringing in Alton, Illinois. Wadlow reached 8 ft 11.1 in (2.72 m) in height and weighed 485 lb (220 kg) at his death at age 22. His great size and his continued growth in adulthood was due to hypertrophy 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 even at the time of his death. 
John William "Bud" Rogan (ca. 1868–1905) is one of twelve individuals in medical history to reach a height of eight feet or more. He was born in Sumner County, Tennessee, United States, between 1865 and 1868. Rogan began to grow very rapidly at the age of 13, leading to ankylosis. Having only been able to walk on crutches, by 1882 he could not stand or walk. By 1899, he had grown to a height of 8 ft 6 in and often appeared in newspapers, referred to as the Negro giant. He got around by way of a goat cart he had made himself and was always the center of attention, often noted for his extremely deep voice and playful attitude. Although he could not work, he made a living by selling portraits and postcards of himself at the train station. His hands measured 11 inches in length and his foot measured 13 inches in length. He continued to grow until his death; his exact height was not measured until after his demise. At that time he measured 8 ft 9 in (269 cm) tall, but weighed only 175 pounds (79 kg), making him the tallest African-American, and the second tallest person, ever recorded. Rogan died in 1905 from complications of his disease. His body was buried in the family yard under solid concrete to stop scientists from robbing and examining his body.
John F. Carroll (1932-1969) is one of twelve individuals recorded in medical history to have stood eight feet or more. Carroll suffered from severe, 2-dimensional spinal curvature (Kyphoscoliosis) and acromegalic gigantism. He had a standing height of 244 centimeters (8 feet 0 inches) on October 14, 1959, but his height would have been 264 centimeters (8 feet 7¾ inches), assuming normal curvature of the spine. He was later measured at 239 centimeters (7 feet 10½inches) in 1968; he had shrunk in stature due to his worsening spinal condition. Shortly before Carroll's death in 1969 his standing height was 234 centimeters (7 feet 8¼ inches). His corrected height was not recorded but may have been close to nine feet. Carroll was born in Buffalo, New York, United States, and also known as the Buffalo Giant in medical literature. Carroll was third in stature only to Robert Wadlow and Willie Bud Rogan. His extraordinary growth started at the age of sixteen and continued until his death, despite extensive treatments at Mercy Hospital. At one point he grew seven inches in height in a matter of a few months.
Väinö Myllyrinne, (27 February 1909, Helsinki – 13 April 1963, Järvenpää, Finland) was an acromegalic giant who was at one time (1961–1963) the world's tallest person. He stood 222 cm (7 feet 3.4 inches) and weighed 197 kg (31 stone) at the age of 21, but experienced a second phase of growth in his late thirties, attaining a height of 251 cm (8 feet 3 inches). Myllyrinne is considered the tallest soldier ever, having served in the Finnish Defence Forces. He was also voted 12th greatest Finn in the TV show Suuret suomalaiset, largely due to a tongue-in-cheek Internet campaign criticising the idea of the show. The advocates of the campaign thought that because one cannot pick just one person to be the Greatest Finn for their accomplishments, Väinö Myllyrinne would actually be the "biggest Finn" because of his height (in Finnish, the word suuri means both "big" and "great"). He had a 15.7 inch hand span, the greatest known. Vaino also had a 2.75 m (9 ft 0.2 in) arm span. 
Sultan Kösen (born December 10, 1982 in Mardin, Turkey) holds the Guinness World Record for tallest living male. He is one of only thirteen individuals in medical history to be confirmed at a height of eight feet or more. Kösen lives with his parents, three brothers and sister, who are all of normal height. He was unable to complete his schooling because of his height and works part-time as a farmer. Despite his height he claims to enjoy a normal lifestyle and enjoys playing computer games with his friends. He describes the advantages of being tall as seeing from great distance, being able to help his family with domestic jobs such as changing light bulbs and hanging curtains. He lists disadvantages as not being able to find clothes or shoes that fit or finding it extremely hard to fit into a regular sized car. 
Bernard A. Coyne (July 27, 1897 – May 20, 1921) Anthon, Iowa, USA. Is one of only twelve individuals in medical history to have stood 8 feet tall or more. Coyne may have reached a height of 8 feet 4 inches (2.49m) tall at the time of his death in 1921. His World War I draft registration card, dated 29 August 1918, lists his height as 8 feet. The Guinness Book of World Records stated that he was refused induction into the Army (1918) when he stood at a height of 7 feet 9 inches. Coyne was the tallest ever eunuchoidal infantile giant, also known as Daddy Long-Legs Syndrome. He was the tallest person in the world at the time of his death when, like Robert Wadlow, he was still growing. He reportedly wore size 25 (American) shoes. Bernard Coyne died of hardening of the liver and of a glandular disorder in 1921. He is buried in Anthon, Iowa, in a specially-made, extra-large coffin.
Donald A. Koehler (September 1, 1925 – February 26, 1981) is one of twelve individuals in medical history to reach a verified height of eight feet (244 cm) or more. He was generally recognized as the tallest man in the world from at least 1969 until his death in 1981. At one time, Koehler stood 249 cm (8' 2") tall, and weighed 320 pounds, a result of the medical condition acromegalic gigantism. He was born in Denton, Montana, USA. Koehler and his fraternal twin sister were born to parents of above average height (their mother was 178 cm (5' 10"), their father was 188 cm (6' 2")). He started an abnormal period of growth when he was 10 years old. The Guinness Book of World Records confirmed Koehler at a standing height of 249 cm (8' 2") in tall at his peak. His twin sister was 175 cm (5' 9") for a record difference of 74 cm (29") between the two twins as recognized by Guinness.
Vikas Kumar "Vicky" Uppal (1986 – June 30, 2007) was a native and resident of India, said to be his country's tallest man until his death. On 12 January 2004, The Tribune reported him to be 8 ft 3 in (2.51 m) tall and still growing, being in his late teens. On 10 June 2005, rediff.com reported him to be 8 ft 10 in (2.69 m) tall. Vikas was from the Haryana state of India, Rohtak district. He was photographed for The Hindu on 25 September 2006 at a rally held by the Indian National Lok Dal. Said again to be 8 ft 9 in tall, he has however been reported otherwise to be an unconfirmed 8 ft 0 in (2.44 m), and born in 1986 was most likely no longer growing. He could have been considered the world's tallest living man, but the Guinness Book of Records has strict verification criteria and did not measure Uppal. He also had been said to have hands 13 inches long and feet 19 inches long, and appears in photographs to be proportionate/not obviously a pathological (acromegalic, for example) giant. Vikas died June 30, 2007 during a failed brain tumor operation in Delhi, India.
Patrick Cotter O'Brien (1760 – September 8, 1806) was the first of only twelve people in medical history to stand at a verified height of eight feet (2.4 m) or more. O'Brien was born in Kinsale, County Cork, Ireland. His real name was Patrick Cotter and he adopted O'Brien as his stage name in the sideshow circuit. He was also known as the Bristol Giant and the Irish Giant. It is believed he died from the effects of the disease gigantism. No hearse could be found to accommodate his nine feet four inch casket encased in lead, and his remains were borne to the grave by relays of fourteen men. In his will, Cotter left £2,000 to his mother and a request that his body be entombed within twelve feet of solid rock (to prevent exhumation for scientific or medical research). In 1972 his remains were examined and it was determined that, while alive, he stood approximately 8 feet 1 inch (246 cm) tall. This made him the tallest person ever at that time, a record that would be surpassed by the next 'eight-footer', John Rogan, who died almost a century later. An arm of Cotter's is currently preserved in the Medical Museum of the Royal College of Surgeons, London.
Julius Koch (1872 in Reutlingen, Germany - March 30, 1902, in Mons, Belgium), also known as Le Geant Constantin, was one of twelve people in medical history who have surpassed eight feet in height. He was a victim of the malady eunuchoidal-infantile gigantism (daddy-longlegs syndrome). His height, 245.9 centimeters, (8 feet, 0.8 inches) was estimated, as his legs were amputated after they developed gangrene. He was probably never the world's tallest person due to his life coinciding with that of John Rogan, who likewise suffered from gigantism. Koch's femurs were the longest on record - 76 centimeters (29.9 inches) - and his hands were 37.5 centimeters (14¾ inches) in length. His feet in some articles are claimed to have a length of 32 inches. Koch died in Mons, Belgium on March 30, 1902. His skeleton is preserved in the Museum of Natural History in Mons. Koch was the star of an early short film, The Giant Constantin, released in 1902.