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?

Every year, thousands of aspiring dancers enter one of the world's most prestigious ballet competitions, the Youth America Grand Prix, where lifelong dreams are at stake. In the final round, with hundreds competing for only a handful of elite scholarships and contracts, practice and discipline are paramount, and nothing short of perfection is expected. Bess Kargman's award-winning documentary, First Position, follows six young dancers as they prepare for a chance to enter the world of professional ballet, struggling through bloodied feet, near exhaustion and debilitating injuries, all while navigating the drama of adolescence. A showcase of awe-inspiring talent, tenacity and passion, First Position paints a thrilling and moving portrait of the most gifted young ballet stars of tomorrow.

In the second episode of the series, the Germanic tribes strike as Marcus Aurelius succumbs to disease, leaving a skeptical Emperor Commodus to prosecute a war that doesn't interest him.

In the third episode of the series, Commodus rises to power as Rome's new emperor, but not everyone supports his ascent. Among those conspiring against him: his older sister Lucilla.

In the fourth episode of the series, Commodus defeats his sister's coup but withdraws from governing, allowing others to amass power while he engages in an affair and banishes his wife.

In the fifth episode of the series, lavish imperial games at the Colosseum are highlighted by the emperor's bloody victories, but his paranoid abuses of power lead to a final betrayal.