Fatal Insomnia Format:DVD The largest reptile on earth

The largest reptile on earth is lurking in the rivers of Australia's Northern Territory

and kill anyone unlucky enough to stand in the way

Is she haunted by evil or is it just the baby blues

a summer meadow is a home to an undiscovered world

After Regina crushes the heart of her Dark Half

Fatal Insomnia Format:DVD The largest reptile on earthYou climb into bed, turn off the light, and close your eyes, but you can't fall asleep. For most of us, it's just one annoying night, but for people with fatal familial insomnia, or FFI, it's the beginning of the end. An extremely rare genetic disease passed down through generations, FFI's primary symptom is sleeplessness, but with a fatal twist: victims are dead within months. To understand FFI, National Geographic delves into the science of sleep