This link to an audio interview was posted previously: http://www.aip.org/history/ohilist/4325.html Gamow talks about meeting Bohr and his wit: He says that he was startled to see a horseshoe nailed above the door to Bohr's house. Gamow asked Bohr why he had it there. Bohr said "I've heard that it works even if you don't believe in it."