The vast and often unexplored wildernesses contained within America's network of national parks play host to a range of bizarre incidents.
A strange series of events in Grand Canyon National Park leads researchers to speculate whether its power comes from forces that cannot be explained. (S1, ep 1)
A plane crash in the Everglades National Park leads to strange hauntings - and some believe the park may exert a dark, transformative power. (S1, ep 2)
The Hawaii Volcanoes National Park is the site of strange events. Are they linked to the legendary Native Hawaiian Goddess of the Volcano, Pele? (S1, ep 3)
Are UFO sightings at Joshua Tree linked to an anti-aging machine and a powerful creature called the Yucca Man? (S1, ep 4)
In Montana's Glacier National Park, some claim that there is a hidden underground Nazi base that may even have been the final hideout for Hitler himself. (S1, ep 5)
From inexplicable disappearances to mysterious experiments, events in Mount Shasta National Park may be explained by an ancient Karuk Indian legend. (S1, ep 6)
Few know that one of the US's most mysterious National Parks is in Puerto Rico - a place some believe is home to a creature known as the Chupacabra. (S1, ep 7)
Many believe Gettysburg National Military Park is haunted by its violent past - here, explore some incredible claims about the park's history. (S1, ep 8)