Edward Teller (1908–2003) was a Hungarian-American theoretical physicist, known colloquially as "the father of the hydrogen bomb". Teller was born in Budapest and emigrated to the United States in 1935. He was an early member of the Manhattan Project charged with developing the first atomic bombs. He was an early proponent of a fusion weapon, which most of his contemporaries believed was infeasible. In 1951, he and Polish mathematician Stanisław Ulam finally made the breakthrough which made the hydrogen bomb possible.Photo: US Department of Energy; Restoration: Greg L/PLW