As the six-year period 2013-2019 is the quadricentennial of the building of the Derry Walls, each year, the Friends of the Derry Walls and its partners unpack an often forgotten historical milestone in the building of this ancient monument, and the legacy it has left on our cultural identities. All activities undertaken during the quatercentenary is branded under Walls400, exploring the contested history that the City Walls represent, and celebrating them as a present-day, national heritage asset, with the potential to unite rather than separate people.