In the third of this new three-part series Neil Oliver, Chris Packham, Andy Torbet and Dr Shini Somara join hundreds of archaeologists from around the world who have gathered there to investigate at one of Europe's biggest digs. Andy Torbet dives below the waves in search of the inspiration for the first stone circle, Chris Packham and Neil Oliver spend the night on an abandoned island as they hunt for clues as to why cultures change, Shini Somara tests the technology behind a bronze age sauna and the archaeologists uncover a remarkable find.