An illustration of a person walking in a dark swamp with will-o’-the wisps People throughout the world, from Asia to Europe, have reported seeing will-o-the-wisps, especially in waterlogged areas.

For centuries, people have reported strange, flickering lights over marshes and cemeteries. In folklore, these lights were called “will-o’-the-wisp” in Britain or “lygtemænd” in Scandinavia. Some ...