Hafþór Júlíus Björnsson (; transliterated as Hafthor in English, born 26 November 1988), is an Icelandic professional strongman who is widely regarded as one of the greatest strength athletes of all time. He is the first and only person to have won the Arnold Strongman Classic, the Europe's Strongest Man, and the World's Strongest Man competitions in the same calendar year and holds numerous Strongman titles from multiple strength federations, including multiple world records. With 30 international competition wins, he is the third most decorated strongman in history, behind Lithuania's Žydrūnas Savickas and Poland's Mariusz Pudzianowski, and in terms of pure brute strength, many strength analysts and strongman experts regard Hafþór as "the strongest man to have ever lived". Hafþór has also appeared in television as an actor, portraying "The Mountain" Ser Gregor Clegane in the HBO series Game of Thrones for five seasons. He is often simply referred to as "Thor" or "The Mountain", as the latter has been closely identified with that character due to his own massive size. Early life Hafþór was born on 26 November 1988 in Reykjavík, Iceland. When he was eleven years old, his family moved to Kópavogur. He received his primary education at Grundaskóli and then Hjallaskóli hill school, but due to high levels of energy as a child, he had difficulty sitting in a classroom or concentrating on his studies. As a student at the polytechnic school in Breiðholt, he was enthusiastic about sports and played soccer and did gymnastics, before discovering his passion for basketball in eighth grade. He was also a chess player, with a Blitz rating of 800. He also loved playing video games. A lanky teenager, Hafþór gained size and strength through daily exercise, combining basic movements (push-ups, chin-ups, and sit-ups) with working at his grandfather's farm during summers and lifting natural stones in the wilderness. His imposing height of 205 cm (6 ft 9 in) is credited to his 203 cm (6 ft 8 in) father, Björn Þor Reynisson, and his mother, Ragnheiður Juliusdottir, who is also of tall stature. Hafþór's grandfather Reynir Ásgeirsson is also very tall and just as broad across the chest. Hafþór has two sisters: Bryndís Björg Björnsdóttir and Hafdís Lind Björnsdóttir. Basketball career Hafþór began his athletic career as a basketball player, playing as a center with a bodyweight of around 105 kg (231 lb). He started his senior team career for