Alaska is the most sparsely populated of all the states. In a vast expanse of rugged wilderness, one area - known as The Alaska Triangle - has been home to so much unusual activity that it has struck fear across Alaska and the world. More people disappear in this area than anywhere else in the United States, with countless sightings of strange creatures, impossible moving lights in the sky, unexplained phenomena and even malevolent ghosts. Are lay lines and electromagnetic anomalies within the Triangle causing these bizarre events? Or is something more sinister at play? From strange reports of military personnel seeing UFOs and missing aircrafts that have vanished without a trace, to sightings of fearful monsters and an underground alien base hidden inside a mountain, each episode of The Alaska Triangle seeks to unlock the paranormal mysteries hidden within this foreboding location.

Some of the world's most incredible engineering projects now lie in ruins. These deserted places are home to extraordinary mysteries and untold secrets, and we revisit them to understand how they were built, and why they were abandoned.They were once some of the most advanced structures and facilities on the planet, standing at the cutting-edge of design and construction. Today they are abandoned, dangerous, some of them even deadly. From uninhabited cities to empty factories, these long-forgotten engineering marvels are scattered around the globe. Science Channel uncovers why some of the world's most advanced architectural achievements were eventually left behind in the all-new series Mysteries of the Abandoned.Each of the six, hour-long episodes of Mysteries of the Abandoned features stories behind engineering wonders, why they were built, and the reasons they were eventually left to crumble. Each story recalls the people who originally designed the structure, their historical significance, and why they were ultimately no longer of use. The premiere episode explores California's Goat Canyon Trestle railway, known as the 'Impossible Railroad,' that required the biggest wooden trestle bridge in the world; Ukraine's Duga, the notorious anti-ballistic missile radar, known as the 'Russian Woodpecker,' that still stands in within the Chernobyl Exclusion Zone; and the Grand Goulets Road in the French Alps, an astonishingly narrow and perilous mountain passageway.

The great outdoors aren't always so great. In fact, the woods are filled with mysteries that sometimes cannot be explained. These are the true accounts of people who ventured deep into the forest only to come screaming out with stories that defy reality.

Secrets of the Dead is part detective story, part true-life drama that unearths evidence from around the world, challenging prevailing ideas and throwing fresh light on unexplained events.[NOTE: Episodes shown only in the UK are listed in Season 0, first digit of episode number indicated UK series.]

Visits to the most remote, cold and inhospitable places on the planet to reveal great mysteries that have been frozen in time.