The countdown of the 50 greatest treasures found by the British public continues from 18 to 11. Jon Culshaw goes on the trail of some Viking treasure which gives a clue to the origins of the north/south divide, Dan Lobb reveals how a Bronze Age stash proves that the import and export business was thriving 3,500 years ago and, in Nottinghamshire, Anita Rani tells the story of a medieval chess piece - a 12th century metal knight. Presented by Michael Buerk and Bettany Hughes.