On Start the Week Andrew Marr talks to the artist Cornelia Parker about the secrets revealed in found objects. Parker's latest exhibition at the Foundling Museum is inspired by the 18th Century tokens left with babies by their mothers. Simon Armitage finds a new way of telling the medieval poem Pearl, an allegorical story of grief and lost love. Archaeologist Cyprian Broodbank explains how Must Farm, the first landscape-scale investigation of deep Fenland, is transforming our understanding of Bronze Age life, while British Museum curator Aurelia Masson-Berghoff celebrates the finding of two lost Egyptian cities submerged at the mouth of the Nile for over a thousand years.