As a mathematician, sometimes I meet across very embarrassing questions which were posted by who does not learn of mathematics, for example, my wife and so on. She or he always posted such questions: Well, you are majored in mathematics, do you know Gauss? Where did he come from? In which country? What did he study in mathematics? etc. Although I maybe answer the mathematical question on my major, I cannot answer such questions, and I always feel very ashamed.
Here is my question: Which mathematics celebrities that you think other mathematicians should know, and why.