It's not a joke or an illusion. Save for the tower, St Laurentii (Laurence) Church is buried in sand. The church dates back to 1387, but in 1795 it had to be closed due to drifting sand. Burials were still held there occasionally until 1810, where the sand made that impossible, too. Below there is a sketch of how the church used to look before the sand came. It was whited when it was decided to use it as a landmark for ships at sea.