The world's tallest man ever was Robert Wadlow, who was 8 feet 11.1 inches (2.72m) tall.
Wadlow was 6 feet tall by the time he was 8 years old. Called the 'Giant of Illinois', he was still growing when he died at age 22. He died from a blister on his foot that got infected. His continued growth in adulthood was due to an abnormally high level of human growth hormone. He was buried in a half-ton coffin that required twelve pallbearers to carry.
The tallest man alive is Sultan Kösen, from Turkey, who stands at 8 feet 1.2 inches tall. Only 14 people have ever been confirmed to be 8 feet tall.