European Heritage Open Days is an annual event celebrating local architecture, history and culture. On 10th & 11th September, the historic buildings, monuments and landmarks of Derry~Londonderry will open, offering free activities for you to enjoy. Soak up the LegenDerry spirit inside the Guildhall, Tower Museum and many of the city’s historical churches. Why not get outdoors and explore the wonders of Boomhall Estate and Creggran Country Park.