Many argue that flying saucers and other extra-terrestrial space ships continuously visit the earth. If that were true, what kinds of technologies would such alien spacecraft require? And do eyewitness reports of UFO sightings jibe with modern theories of how interstellar travel might be possible? Authors, astronomers and theoretical physicists weigh in with the blueprints for inertia-canceling devices, nuclear-powered craft, antimatter propulsion systems and even warp drives. Based on Einstein's theories and countless scientific studies, we'll find out how these visitors might bridge the vast distances between the stars. And if they could survive such hazardous journeys, are they flesh and blood or intelligent machines?

This series shines a spotlight on the influential builders, dreamers and believers whose feats transformed the United States, a nation decaying from the inside after the Civil War, into the greatest economic and technological superpower the world had ever seen. The Men Who Built America is the story of a nation at the crossroads and of the people who catapulted it to prosperity. In the first episode, Cornelius Vanderbilt grows from a steamboat entrepreneur to the head of a railroad empire, and gets into a heated rivalry with Jim Fisk and Jay Gould; the up and coming John D. Rockefeller founds Standard Oil. Many business owners lay their own rail lines which leads to the Panic of 1873. Later, Rockefeller starts to expand his wealth by diverting his business from the railroads to a new innovation, oil pipelines.

In the second episode, Professor Iain Stewart discovers how flowers have transformed our planet. He journeys to the remote islands of the South Pacific to track down the earliest flowers. In the deserts of Africa and rainforests of Vietnam, he sees how they brought brilliant colour to the most barren landscapes and sculpted the earth itself. And he learns how they drove the evolution of all animals - kick-starting our human story.

Professor Jim Al-Khalili investigates the amazing science of gravity. A fundamental force of nature, gravity shapes our entire universe. It sculpts galaxies and warps space and time. But gravity’s strange powers also affect our daily lives in the most unexpected ways. This is a story with surprises in store for Jim himself. In telling the story of gravity, his own understanding of the nature of reality comes to be challenged. Finally, Jim discovers that, despite incredible progress, gravity still has many secrets to unveil.

In the third episode, prominent adventure sports photographer Krystle Wright captures the immersive world of free-diving in Vanuatu, athletes who appear to walk on air in the canyons of Colorado, and powered para-gliders on the flooded salt pans of Utah.

This spellbinding documentary follows Aisholpan, a 13-year-old nomadic Mongolian girl who is fighting an ingrained culture of misogyny to become the first female Eagle Hunter in 2,000 years of male-dominated history. Through breathtaking aerial cinematography and intimate verite footage, the film captures her personal journey while also addressing universal themes like female empowerment, the natural world, coming of age and the onset of modernity.