The shimmering dunes of White Sands National Park harbor an extraordinary secret: fossilized human footprints that suggest human presence in the Americas as much as 10,000 years earlier than previously believed. How did these footprints in the sand manage to survive for so long? And why is their discovery changing everything we thought we knew about human history in the region? Untold Earth explores the seeming impossibilities behind our planet’s strangest, most unique natural wonders. From frag

327K views · 36 reactions | You'll lose your head over this video from #Monstrum! This week Dr. Emily Zarka talks about the history behind the Headless Horseman and the Irish folklore of the Dullahan. | PBS Digital Studios | Facebook