When Albert Einstein discovered that E=mc2, he saw in the equation the answer to why the Sun shines. But others read into it a darker meaning. This program—part documentary with compelling graphics, part dramatization—explains how Einstein’s great achievement was also, in his own words, his "biggest blunder." A close look at the scientific relationship between energy, mass, and the speed of light sets the stage for the gripping drama in which Nazi Germany and the United States vied to make the world’s first true weapon of mass destruction. Commentary by Brian Cox and Robin Marshall, of The University of Manchester; authors Richard Rhodes, Peter Galison, and William Lanouette; and other experts is featured. A BBCW Production. (50 minutes)