Walls 400! will mark the quarter-centenary of the city walls with a series of activities to explore the contested history that the city walls represent and to celebrate Derry’s walls as a present-day national heritage asset, with the potential to unite rather than separate people. In 1613, two representatives from the city of London, Alderman George Smithes, and Merchant Taylor Mathias Springham, along with 10 local officers, ‘viewed and trode out the ground at the Derry for the fortification there.’ That initiative granted the city the largest ancient monument in Northern Ireland in the creation of the city walls; it also left an enduring imprint on the cultural identities of the people of Ireland and Britain. Walls 400! will mark the quarter-centenary of the city walls with a series of activities to explore the contested history that the city walls represent and to celebrate Derry’s walls as a present-day national heritage asset, with the potential to unite rather than separate people. The year-long programme of activities is developed by the Holywell Trust’s City Walls Heritage Project, working in partnership with Derry City Council, DOE Northern Ireland Environment Agency, and the Walled City Cluster of community-based, cultural tourism attractions.