What actually took place in a secret meeting in 1941 between Niels Bohr, who is considered the father of quantum physics, and Werner Heisenberg, who was working on, but failed to create, the atomic bomb for Nazi Germany?

Bohr had been Heisenberg's mentor, and the two scientists had collaborated and brought forth the basic tenets that would become the foundation of quantum physics. Heisenberg was a German; Bohr was half Jewish, and living in Nazi-occupied Denmark. Bohr’s house was wiretapped, so when Heisenberg appeared at Bohr’s doorstep, the two men took a walk so that no one could record their conversation. All that was publicly known was that after the meeting, Bohr would have nothing to do with Heisenberg.

Playwright Frayn said "The heart of Copenhagen is how we know why people do what they do, and even how one knows what one does oneself."

This brilliant play won all the major awards, including the Tony for Best Play.