Ghosts from a bizarre plane crash and a mysterious underground city point to powerful forces at work inside the Grand Canyon National Park.

A tragic plane crash, shocking murders, and mysterious python infestation suggest a dark, evil power at the heart of Florida's Everglades National Park.

Black magic, mysterious deaths, and violent fireballs haunt Hawaii's Volcanoes National Park. Many believe this is the work of Pele, the fire goddess.

A Bigfoot-like creature and UFO sightings suggest that California's Joshua Tree National Park may be ground zero for alien genetic experiments.

A secret, underground Nazi base may be the reason for UFO sightings in Montana's Glacier National Park. It may also be the final hideout for Adolf Hitler himself.

Unexplained disappearances, a mysterious death and a Karuk Indian legend may be linked to a race of superhumans in California's Mount Shasta National Forest.

The fabled Chupacabra in Puerto Rico's El Yunque National Forest may be linked to UFO sightings in the area and a secret US government research facility.

Ghost sightings, a secret government time-travel experiment, and Native American battles suggest that Pennsylvania's Gettysburg National Military Park is a place of unusual and mysterious power.