Professor Alexander Thom puts forward his theory that Stonehenge and other megalithic sites were used to record time and predict solar and lunar eclipses. Magnus Magnusson looks at Thom's evidence and hears what different archaeologists think of the suggestion that Stone Age Britons could make such elaborate calculations. If Thom's theory is correct, previous archaeological certainties about the knowledge and ability of people in the Stone Age would be overturned.
One of the great engineering masterpieces created by Isambard Kingdom Brunel had been left to rot in the South Atlantic since 1937. This is the story of how SS Great Britain was rescued from the icy shores of the Falkland Islands and why it is so important to 19th-Century maritime and engineering history. The 'Chronicle' film crew are on hand to record the breathtaking efforts of the rescuers, who remove the enormous hulk from the South Atlantic and transport her on a final journey that ends with her passing under the Clifton Suspension Bridge into Bristol.