Big History - Season 1 Episode 9 Mountain Machines

They form natural boundaries, dictate how we spread around the planet, create natural defenses, and control our weather. From the World War that began with a gunshot in the Balkans to the feuds of the Appalachians, mountains have also been flashpoints for violence. They provide minerals and metals that make civilization possible, and the water that feeds billions, yet we were never designed to live in their extreme environments. Without mountains earth would be desolate and uninhabitable, and scientists now believe that an invisible mountain range made life possible ...