Who is Niels Bohr from Surely You're Joking, Mr. Feynman! and what is their importance?

Even among the elite selection of distinguished scientists who work at Los Alamos, Niels Bohr is a god-like figure. Bohr likes speaking to Feynman, who is at the time young and unknown, because he is the only scientist at Los Alamos who is not too intimidated by Bohr's fame to argue with him.