Episode 6

This week Dan Cruickshank reveals the untold story of Britain's imperial strength when he visits what was the Royal Gunpowder factory at Waltham Abbey in Essex. Actress Sorcha Cusack journeys back to her childhood home in Dalkey lsland, near Dublin. And Newsnight presenter Kirsty Wark investigates the rebuilding of a medieval palace in London on the banks of the River Thames.