Ancient astronomical instruments from 1,600BC and 5,000BC Germany, marking the Pleiades / equinoxes and solstices. From Richard Rudgley's "Pagans - Magic Moments", except they cut this part out now (shows have 3-4 minutes more adverts than they used to). Funny, as this is the best bit of the whole show, which isn't great. His "Secrets of the Stone Age" is much better and on 4oD, as is the special "The Celts" http://www.channel4.com/programmes/the-celts/4od