Haderslev Cathedral (Haderslev Domkirke) — also known as Our Lady's Church — is the seat of the Diocese of Haderslev and the town's most impressive building by a considerable margin. The Gothic red-brick structure dates to the 13th century, though the current form reflects centuries of additions and restorations. The interior is spacious and atmospheric, with vaulted ceilings, a carved Renaissance altarpiece, and medieval floor tiles still in place in parts of the nave.
The cathedral stands in the historic centre of town, surrounded by well-preserved old houses. It is free to enter and worth at least half an hour inside — the acoustics are exceptional, and if you visit during organ practice you will understand why the church has hosted notable musical events for centuries.