Series examining how the BBC has revealed and interpreted moments in history, as well as looking at changes in research covered in documentary television. In the first edition, Professor Alice Roberts uses 70 years of BBC history archive to uncover how Stonehenge has been explained, argued over and debated by some of Britain's leading historians and archaeologists. She looks at how new theories discredited old ones, how astronomers and geologists became involved, and why, even after centuries of study, there is still no definitive answer to the mystery of Stonehenge