 The BBC2 broadcasts of the first two series have a slightly shorter running time and contain less information than the original National Geographic broadcasts, with on average one minute of footage cut from every episode.None of the three series of the programme are available to purchase on DVD in the UK, however, all three can be watched on demand for subscribers of National Geographic on Sky, Virgin Media and BT Vision.In Australia, all three series are available on DVD, either separately or as a box-set.