The Sand-Covered Church — Den Tilsandede Kirke in Danish — is all that remains of a 14th-century parish church that was engulfed by migrating sand dunes over several centuries. The white tower stands alone in a treeless dune landscape about 2 km south of central Skagen, and the effect is genuinely eerie: a Gothic steeple rising from a flat, sandy wilderness.
The church interior is long gone, but you can climb the dunes around the tower and get a good sense of how completely the sand overwhelmed the structure. It's an easy bike ride from town, and worth combining with a walk along the west beach.