A grim discovery in a Swedish lake reveals shocking ancient practices. Meanwhile, in the Canadian Arctic, the fossil of a previously unknown mammal is found.

In a Danish bog, hundreds of mutilated ancient bones are found, while a mysterious deserted island belonging to Russia is explored.

Archaeologists in Russia find several mass graves, a World War II plane sits on a Canadian mountain, and cosmic rays in Antarctica stump experts.

Human remains are discovered high in the Ecuadorian Andes, while a strange earthquake-like event is investigated in Canada.

In Russia, 34,000-year-old graves are discovered. Meanwhile, a team attempts to locate a British World War II aeroplane that went missing in Iceland.

A mysterious volcanic island off the coast of Antarctica is explored, while the mummified remains of a teenage girl are found in the Peruvian Andes.

Mysterious industrial waste is discovered in an uninhabited part of Greenland. Meanwhile, strange mounds are found deep within the Arctic Circile.

A secret military base is discovered a few hundred miles from the North Pole. A man-made, ancient stone formation is found 120 feet below the surface of Lake Huron. A 1500 year old burial ground is discovered on the shores of the Baltic Sea. And in Russia's far east, a life-form that scientists think can live for thousands of years is discovered in the permafrost.

A giant naval vessel is located on the bottom of the Norwegian Sea. An ancient reptile-like creature unknown to science is found in the permafrost of Canada's Arctic. In Scotland, archaeologists are drawn to a strange, figure-eight shaped ditch. An Antarctic research base finds itself suddenly surrounded by blood soaked snow.