'The Coldest War': With the polar ice caps shrinking due to global warming, new trade routes are being exposed, along with billions of dollars' worth of natural-resource reserves. The five nations bordering the Arctic are readying themselves to fight for it. The problem is that there's one non-NATO country that already considers itself rightful owner of the region: Russia. With Vladimir Putin's recent military annexation of Crimea, there's a definite possibility its aggressions will boil over, returning the international community to precarious Cold War footing. We will head north to witness NATO forces participating in the largest polar military exercise in history. 'Heroin Warfare': Since the U.S. occupation of Afghanistan, heroin production in the region has skyrocketed, making the country the number-one producer by a large margin. Though Iran, Afghanistan's neighbor, is an ultraconservative country, Afghan heroin flowing across the border has actually caused Iran to have the worst heroin use problem in the world. Suroosh Alvi gets a rare look inside Iran to meet the suffering heroin addicts, and see how the country is coping with the illegal drug trade.

Researchers discover film footage from World War II that turns out to be a lost documentary shot by Alfred Hitchcock and Sidney Bernstein in 1945 about German concentration camps liberated by allied troops. When Allied forces liberated the Nazi concentration camps in 1944-45, their terrible discoveries were recorded by army and newsreel cameramen, revealing for the first time the full horror of what had happened. Making use of British, Soviet and American footage, the Ministry of Information’s Sidney Bernstein (later founder of Granada Television) aimed to create a documentary that would provide lasting, undeniable evidence of the Nazis’ unspeakable crimes. He commissioned a wealth of British talent, including editor Stewart McAllister, writer and future cabinet minister Richard Crossman – and, as treatment advisor, his friend Alfred Hitchcock. Yet, despite initial support from the British and US Governments, the film was shelved, and only now, 70 years on, has it been restored and completed by Imperial War Museums. This eloquent, lucid documentary by André Singer (executive producer of the award-winning The Act of Killing) tells the extraordinary story of the filming of the camps and the fate of Bernstein’s project, using original archive footage and eyewitness testimonies.

World War II is a watershed event for Latino Americans with hundreds of thousands of men and women serving in the armed forces, most fighting side by side with Anglos. In the Pacific, East L.A.'s Guy Gabaldon becomes a Marine Corp legend when he singlehandedly captures more enemy soldiers than anyone in US military history. But on the home front, discrimination is not dead: in 1943, Anglo servicemen battle hip young "Zoot suitors" in racially charged riots in southern California

Until World War II, Latino immigration to the United States was overwhelmingly Mexican-American. Now three new waves bring large-scale immigration from Puerto Rico, Cuba, and the Dominican Republic. As the Puerto Rican government implements a historic overhaul over a million Puerto Ricans are encouraged to leave for the US mainland, to alleviate the economic pressure. A young Juanita Sanabria arrives in New York, works hard in the garment district, but encounters hostility and discrimination. Ethnic tensions explode in youth gang warfare depicted in films like West Side Story, etching the stereotype of the knife wielding Puerto Rican in the American consciousness.

D-Day: As It Happens D-Day: As It Happens tells the story of this pivotal event in 20th-century history in a completely new way. Using newly-analysed archive footage, viewers can track the progress of seven people who were there on the day, each of them a real participant in the 1944 invasion. And they can do so moment by moment in real time, encountering the twists and turns of the fighting at the same time as the D-Day seven did, and learning their fate as the action unfolds in parallel with the present, Narrated by Peter Snow, with Channel 4 presenter and former marine Arthur Williams, and experts including former British Army officer Colonel Tim Collins and front-line journalist Lorna Ward. The first programme tells the back stories of the real people that the event is following in real time and sets out their missions over the following 24 hours. The D-Day seven include a paratrooper, a midget submariner, a nurse and a military cameraman.

Series concludes with the focus shifting to the United States in the post-war years of the 1950s and beyond. Beginning with arguably the most notorious work of 20th century classical music, John Cage's 'silent' composition 4'33", it looks at how a series of maverick Americans re-invented the sound of classical music into a more simple form, bringing back harmonies and rhythms that made it increasingly popular with audiences across the world. It also examines how this music found its way into a spiritual realm, with the strain of pared-down religious composition that came to be known as 'holy minimalism'. From the Maverick concert hall in Woodstock, New York to an Orthodox cathedral in Estonia to a car park in Peckham, south London, the story is told by a stellar line-up of contributors including Philip Glass, Steve Reich, John Adams, Arvo Pärt and John Tavener.