The Celts - one of the world's most mysterious ancient people. In Britain and Ireland, we are never far from our Celtic past but in this series Prof. Alice Roberts and archaeologist Neil Oliver travel much further afield, discovering the origins and beliefs of these Iron Age people in artefacts and human remains right across Europe, from Turkey to Portugal. What emerges is not a wild people on the western fringes of Europe, but a highly sophisticated tribal culture that influenced vast areas of the ancient world - and even Rome". Rich with vivid drama reconstruction, we recreate this pivotal time and meet some of our most famous ancient leaders - from Queen Boudicca to Julius Caesar - and relive the battles they fought for the heart and soul of Europe. Alice and Neil discover that these key battles between the Celts and the Romans over the best part of 500 years constituted a fight for two very different forms of civilisation - a fight that came to define the world we live in today. In the first episode, we see the origins of the Celts in the Alps of central Europe and relive the moment of first contact with the Romans in a pitched battle just north of Rome - a battle that the Celts won and that left the imperial city devastated.

It's June 1942 and the world's fate is about to be decided by a handful of pilots and their untested aircraft. Experience an inside look at the Battle of Midway, captured through rarely seen battle footage and first-hand accounts from its hero dive-bombing pilot, "Dusty" Kleiss. This is an hour-by-hour recount of one of the most pivotal conflicts of the 20th century. Take a closer look at how this desperately needed victory came about through the design of U.S. air planes, the skill of the pilots, the element of surprise, and a stroke of luck.

The second episode looks at the challenges of hunting in the Arctic, the most seasonal place on Earth. To a predator, seasonal change is a problem. It means that all the parameters of the hunt - the conditions, the strategies, the prey - change too. The only option for the Arctic's top predators, the wolf, the Arctic fox and the polar bear, is to continually adapt to their changing world, exploiting the good times and enduring the bad.

Filmmaker Daniel McNicoll explores the emerging movement to reclaim the ancient medieval and renaissance martial arts in this documentary narrated by Welsh actor John Rhys-Davies, and produced on corroboration with Lord of the Rings director Peter Jackson. The Medieval and Renaissance blade was a remarkable weapon crafted with the utmost attention to detail. Though the history of the sword remains largely shrouded in mystery for younger moviegoers, their presence on the big screen can still be felt in the Star Wars saga, as well as films like Chronicles of Narnia and The Pirates of the Caribbean. Join host Davies as he traces the history of this remarkable weapon throughout the ages, in the process giving us a better understanding of the sword's unique role in both history, and films.

At first glance, Matthew Vandyke —a shy Baltimore native with a sheltered upbringing and a tormenting Obsessive-Compulsive Disorder diagnosis— is the last person you’d imagine on the front lines of the 2011 Libyan revolution. But after finishing grad school and escaping the U.S. for 'a crash course in manhood,' a winding path leads him just there. Motorcycling across North Africa and the Middle East and spending time as an embedded journalist in Iraq, Matthew lands in Libya, forming an unexpected kinship with a group of young men who transform his life. Matthew joins his friends in the rebel army against Gaddafi, taking up arms (and a camera). Along the way, he is captured and held in solitary confinement for six terrifying months.

For decades some have suspected that there might be others out there, intelligent beings capable of communicating with us, even visiting our world. It might sound like science fiction, but today scientists from across the globe are scouring the universe for signals from extraterrestrials. Horizon obtained exclusive access to film researchers at the Green Bank Telescope searching for radio signals from Tabby's Star, a star so mysterious that some scientists believe it might be surrounded by a Dyson Sphere, a vast energy collector built by advanced aliens.