The split stone. A long time ago a troll lady living on the island of Bornholm got annoyed by the church bells in Glemmingebro. She threw a big rock at the church using her garter. Weakened by the sun that just started raising she missed and the stone landed in a field instead, laying there ever since. If you walk through the passage your vision is bewitched, you won't recognize your wife anymore, instead you go to bed with your neighbor's wife. The spell isn't lifted until you walk backwards through the stone again.