Butterflies have been flying around the planet for over 50 million years, and today around 20,000 different species inhabit the globe. From egg to caterpillar to chrysalis to the winged insect, this follow their life stages, highlighting their survival techniques and the new science that is unlocking the secrets of their world and changing the view of these fantastic and yet fragile creatures.

A tribute to comedians of early television, combining archival footage and interviews with such stars as Milton Berle, Red Skelton, Bob Hope, Sid Caesar, Steve Allen, Morey Amsterdam, Rose Marie, Donald O'Connor, Sammy Davis Jr., Buddy Ebsen, and others.

Dolores Huerta is among the most important, yet least known, activists in American history. An equal partner in co-founding the first farm workers unions with Cesar Chavez, her enormous contributions have gone largely unrecognized. Dolores tirelessly led the fight for racial and labor justice, becoming one of the most defiant feminists of the twentieth century.

Martin Luther nailed his treatise to the doors of the Wittenberg Cathedral and forever changed the Christian world. This previously obscure German monk unleashed forces that would plunge Europe into war and chaos. He offered the Christian world a new vision of man's relationship with God and, in turn, redefined man's relationship with authority in general, bringing the collapse of the medieval world and the birth of the modern age.

Reviews the history of the National Parks system in the United States.

Explores and compares aspects of behavior in bird species around the world, including flight, communication, courtship, and parenting, as well as birds' varied diets and habitats.

Murdered more than 5,000 years ago, Otzi the Iceman is the oldest human mummy on Earth. Now, newly discovered evidence sheds light not only on this mysterious ancient man, but on the dawn of civilization in Europe.

On August 15th, 1914, the Panama Canal opened, connecting the world's two largest oceans and signaling America's emergence as a global superpower. This film, using an extraordinary archive of photographs and footage, interviews with canal workers, and firsthand accounts of life in the Canal Zone, unravels the remarkable story of one of the world's most significant technological achievements.

Samuel Clemens rose from a hardscrabble boyhood in the backwoods of Missouri to become, as Mark Twain, America's best-known and best-loved author. Considered in his time as the funniest man on earth, Twain was also an unflinching critic of human nature who used his humor to attack hypocrisy, greed and racism. He created some of the world's most memorable characters as well as its most quoted sayings. And, in his often-misunderstood novel "Huckleberry...

The Pacific Ocean covers one third of the Earth₂s surface, holds half of the world₂s water, and hides the deepest place on the planet. It is a place where huge and iconic, rare and dazzling creatures live, and where creatures yet to be discovered lurk. Filmed in cinematic 4K, the program breaks the boundaries between land and sea to present the Pacific Ocean in a way never seen before.