The Great Northern War pitted the Swedish Empire at the peak of its power against its southern and eastern neighbors, Denmark, Poland-Lithuania, Saxony and seemingly weak and backward Russia in a war that raged from 1700-1721.  The Swedish army was the terror of Europe and was led by Sweden's young king, Charles XII, who had ascended the throne at the age of 18 when his father suddenly died.  In the opening years of the war, Sweden systematically crushed each enemy in turn, beginning with Denmark who surrendered after only four months of contending with Charles' military killing machine.  One by one every kingdom withdrew from the war until there was only one.  The weakness and backwardness of Russia's armies were also exposed early in the war at Narva when Sweden's army routed a Russian force three times its size, but withdrawing into its vast hinterland, Tsar Peter the Great completely reorganized his army.  By 1709, Peter was ready for a showdown with the "invincible" army of Sweden at Poltava.  The complete triumph of Russia over Sweden in this unusual battle marked the entry of Russia into Great Power status in Europe, a status that continues to this day.  Listen to how the world was forever changed in this titanic contest over two decades and the story of two young monarchs thrust by history into greatness and tragedy.