Half a century ago, Crosby, Stills, Nash & Young released one of the greatest albums of the rock era, "Déjà vu." The record would sell eight million copies, but the band, and the friendships, did not endure. Anthony Mason reports. https://cbsn.ws/3wwKyPL | CBS Sunday Morning

Stephen Hawking first appeared on the BBC in the 1977 documentary The Key to the Universe: The Search for the Laws of Creation | BBC Archive