Greystones to Dublin At Trinity College, Dublin, Michael Portillo discovers one of Ireland's greatest treasures and learns how it became the symbol of the nation. There is a chance to sample the black stuff in a Dublin pub before Michael learns how Victorian royals were deployed to calm rocky relations between Britain and Ireland. He explores the magnificent house and gardens of Powerscourt in County Wicklow. Finding an angle on triangulation helps Michael to understand how Ireland was put on the map - and why.