As of 5 July 2016, the United States Strategic Command tracked a total of 17,852 artificial objects in orbit about the Earth, including 1,419 operational satellites. Take a look at the mounting threat of debris in Earth's atmosphere, the potential dangers of such 'junk' and what can possibly be done to avoid a crisis. The film is a visually explosive journey of discovery that weighs the solutions aimed at restoring our planet's orbits.

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.

Rockefeller, Carnegie and Morgan team up to help elect William McKinley to the U.S. presidency by paying for his 1896 campaign, to avoid a possible attack on monopolies. However, fate intervenes when McKinley is suddenly assassinated, and vice president Theodore Roosevelt assumes the presidency and promptly begins dissolving monopolies and trusts in America. Meanwhile, Morgan buys out Carnegie Steel to make Carnegie the richest man in the world, and Henry Ford designs an affordable automobile with his Model T and starts his own business, Ford Motor Company, which sets a new business model for companies to follow.

Everyone has an opinion on bad cars. Now it's time to hear the ones that really count - ours. We're out to name and shame the most rubbish car from a manufacturer which, frankly, should have known better. And we have a special, surprise fate in store for the car we pick as our biggest loser. In this Top Gear special episode, Jeremy Clarkson and James May try to look for the worst car of all time and the criteria was that the car had to be 'terrible, but not cheap' and made by 'a manufacturer that should have known better'.

To fly like a bird, Earthflight not only captured remarkable images of wild flocks but also relied on some extraordinary relationships between people and birds. Filmed over four years, in six continents and more than 40 countries, the Earthflight team used many extraordinary techniques. For some of the unique flying shots, members of the team became part of the flock. The birds followed wherever they went - even in a microlight over Edinburgh and London. In Africa, paragliders floated alongside wild vultures, while a model vulture carried a camera inside the flock. In South America, wild-living macaws, that were rescued as babies, still come back to visit their 'foster mother' as he travels along a jungle river. In Africa, a radio-controlled 'drone' silently infiltrates masses of pink flamingos without disturbing a feather, and microlights and helicopters capture the dramatic moment white storks arrive over Istanbul. In Africa a tame vulture carried a camera across the African bush and recreated the behaviour of his wild relatives. Similarly, in the USA, a flock of hand-reared snow geese followed the migration route of wild flocks and took in the sights and sounds of New York - managing to get lost in Brooklyn

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?