Georg Cantor was born in St. Petersburg, Russia on March 3, 1845, but moved to Germany when he was eleven years old. His mathematical results were numerous and diverse, but what I find most interesting about his career was his work on the concept of infinity. He was actually able to prove the existence of MULTIPLE infinities! For an example of how this works, consider two sets of numbers: the natural numbers and the real numbers. The natural numbers are "countable", meaning you can enumerate them (write them in order): 1,2,3,4,.... The real numbers cannot be enumerated, and thus are "uncountable." Cantor was able to show that uncountable sets have more elements than countable sets. Thus the there are more real numbers than natural numbers, even though there are an infinite number of each. It turns out that there are an infinite number of infinities, but I won't go into that. Cantor did a lot of other interesting and important things that I don't have room to list. He died on January 6, 1918 in a mental institution.