Alice Roberts visits the north of Britain to look at the most fascinating archaeology uncovered in the region over the course of 2021. In North Yorkshire, a team of community volunteers are digging down beneath Richmond Castle. On the northern tip of the Orkney Islands, the dig diary cameras are present to witness archaeologists racing to unearth rare discoveries from an endangered Neolithic tomb before it erodes into the sea. And 10 miles east of Edinburgh, volunteers are hunting for evidence of Scotland's oldest railway