Alan Turing broke the German Enigma code during World War II and devised the Turing machine and the Turing test of computer intelligence. Unabashedly gay, he committed suicide after being convicted of homosexual acts.

Thorvald Nicolai Thiele was a Danish astronomer, actuary and mathematician, most notable for his work in statistics, interpolation and the three-body problem.

Abraham Wald was a mathematician born in Cluj, in the then Austria–Hungary (present-day Romania) who contributed to decision theory, geometry, and econometrics, and founded the field of statistical sequential analysis.