High in the northern Black Forest, Mummelsee—known locally as “Demon Lake” or “Witch’s Lake”—has inspired centuries of dark legend. Folklore tells of water spirits and witches who rose from the depths on stormy nights to dance across the lake’s surface. In the 19th century, locals claimed to see glowing figures gliding above the mist before vanishing into the water. Modern hikers report strange ripples forming without wind and disembodied footsteps circling the shore after dusk. The lake’s depth and unnaturally still surface have fueled persistent rumors that it conceals a gateway to another realm. A stone altar on the lakeshore marks the spot where early travellers made offerings to appease what they called the “lord of the lake.”