These elusive blue flames have been reported globally and inspired a wealth of folklore. But what exactly is a Will-o’-the-Wisp? Also commonly called “ignis fatuus” or “corpse-candle” the glowing atmospheric phenomenon has a reputation for causing mischief and even death. But are they really a supernatural phenomenon or something more worldly? Drawing on over six hundred years of literature and lore, and more than 300 years of scientific exploration, this episode presents the mesmerizing lights in all their blazing glory—from ancient legends to scientific rationalizations. And no, they aren’t glowing owls.