This week we pay homage to Enrico Fermi, the co-inventor of the nuclear reactor. Fermi came to the US in 1938 to escape Mussolini's fascist dictatorship. From The Atom Archive website:
Enrico Fermi was born on September 29, 1901, in Rome, Italy. At age 14, he became interested in the study of physics as a way of coping with his grief over losing his brother Giulio during minor surgery. In 1922, he graduated with a doctorate from the prestigious "Sculoa Normale Superiore" of Pisa, a special university-college for selected gifted students.
In 1923, Fermi was awarded a scholarship from the Italian government and spent several months with Professor Max Born in Gottingen. In 1924, with a Rockefeller Fellowship, he moved to Leyden to work with P. Ehrenfest, and later that year he returned to Italy to occupy the post of Lecturer in Mathematical Physics and Mechanics at the University of Florence, a position that he held for two years.
In 1926, Fermi discovered the statistical laws, nowadays known as the "Fermi statistics," governing the particles subject to Pauli's exclusion principles (now referred to as fermions, in contrast with bosons, which obey the Bose-Einstein statistics). The next year, Fermi was elected Professor of Theoretical Physics at the University of Rome, a post that he retained until 1938 when he emigrated to America, primarily to escape Mussolini's fascist dictatorship. Fermi was also awarded the 1938 Nobel Prize in Physics "for his demonstrations of the existence of new radioactive elements produced by neutron irradiation, and for his related discovery of nuclear reactions brought about by slow neutrons."
You can read more about Fermi and his work at the Nobel Prize website.