The Day After Trinity, 1981 documentary by Jon Else providing a detailed biography of J. Robert Oppenheimer, who was the head of the famous Manhatten project.
Despite being called "The Day After Trinity", this film mainly focuses on Oppenheimer's life before he got involved in making the atomic bomb. It does, however, feature some footage showing his reflection on his contribution to unlocking the power of the atom.
The video quality of this embed from archive.org is not particularly good. It is certainly watchable though and the audio is good. The information provided definitely makes it a must watch for those of you who are interested in learning more about the origins of the nuclear age.