S1, E2: Anglesey, an island off the northwest coast of Wales, lies in waters so tempestuous, Lord Nelson said, ‘if you can sail here, you can sail anywhere’. This engrossing travel documentary unearths the area’s hidden treasures, including the wild ponies of Newborough Warren, the Anglesey shipwreck that changed the way we forecast the weather forever and the factory that pays the King to extract salt.