Professor Jim Al-Khalili sets out to discover whether nuclear power is safe. He begins in Japan, at the former Fukushima nuclear plant, where he meets some of the tens of thousands of people who have been evacuated from the exclusion zone. He travels to an abandoned village just outside the zone to witness a nuclear clean-up operation. Jim draws on the latest scientific findings from Japan and from the previous explosion at Chernobyl to understand how dangerous the release of radiation is likely to be and what that means for our trust in nuclear power.

The fifth programme explores the alliances formed between the animal and plant worlds. Attenborough dives into Australia's Great Barrier Reef and contrasts the nocturnal feeding of coral, on microscopic creatures, with its daytime diet of algae. Some acacias are protected by ants, which will defend their refuge from any predator. Besides accommodation, the guards are rewarded with nectar and, from certain species, protein for their larvae as well. Fungi feed on plants but can also provide essential nutriment to saplings (Mycorrhiza). The connection is never broken throughout a tree's life and a quarter of the sugars and starches produced in its leaves is channelled back to its fungal partners. Meanwhile, fungi that feed on dead wood leave a hollow trunk, which also benefits the tree. Orchids enjoy a similar affiliation. Lichens are the product of a relationship between fungi and a photosynthetic associate, usually algae. They are extremely slow-growing, and a graveyard is the perfect location to discover their exact longevity. Mistletoe is a hemiparasite that obtains its moisture from a host tree, while using own leaves to manufacture food. Its seeds are deposited on another by the mistletoe tyrannulet, following digestion of the fruit. The dodder (Cuscuta) is also parasitic, generally favouring nettles, and siphons its nourishment through periodic 'plugs' along its stem. The rafflesia has no stem or leaves and only emerges from its host in order to bloom — and it produces the largest single flower: one metre across.

The Sea of Cortez, also known as the Gulf of California, is a unique corner of the Pacific Ocean. This remarkable young sea is thought to be around five million years old and home to nearly 900 species of fish and the widest variety of whales and dolphins found anywhere on Earth. Some of the greatest changes threatening the world's oceans today can be seen in this stretch of water.

Filmmaker Robert Kenner lifts the veil on our nation's food industry, exposing the highly mechanized underbelly that's been hidden from the American consumer with the consent of our government's regulatory agencies, USDA and FDA. Our nation's food supply is now controlled by a handful of corporations that often put profit ahead of consumer health, the livelihood of the American farmer, the safety of workers and our own environment. We have bigger-breasted chickens, the perfect pork chop, insecticide-resistant soybean seeds, even tomatoes that won't go bad, but we also have new strains of e coli--the harmful bacteria that cause illness for an estimated 73,000 Americans annually. We are riddled with widespread obesity, particularly among children, and an epidemic level of diabetes among adults Featuring interviews with such experts as Eric Schlosser (Fast Food Nation), Michael Pollan (The Omnivore's Dilemma) along with forward thinking social entrepreneurs like Stonyfield Farms' Gary Hirschberg and Polyface Farms' Joe Salatin, the film reveals surprising--and often shocking truths--about what we eat, how it's produced, who we have become as a nation and where we are going from here.

Al Capone moves back to Chicago and takes over two floors of the city's finest hotel, the Lexington. With a thriving business and Chicago politicians in his back pocket, Capone soon reaches a level of celebrity normally reserved for athletes and entertainers. As Capone's profile grows, he begins to indulge in all that the Roaring '20s have to offer, including cocaine. While Capone enjoys his reign at the top of the Chicago underworld, Irish gangster Bugs Moran seeks to take him down as revenge for the deaths of his partners Dean O'Banion and Hymie Weiss. On March 7, 1928, Moran orders a hit on one of Capone's top associates, Jack McGurn, the man who took out Hymie Weiss. McGurn survives but Capone decides to retaliate by taking out Moran and as many of his men as possible - all at once. On February 14, 1929, Capone's men dress as law enforcement and raid the liquor buy. They order Moran's men to face the wall for handcuffing, but while their backs are turned, Capone's men shoot all of them. Firing 70 rounds of ammunition in less than 10 seconds, the assassins carry out the biggest gangland hit in American history that will come to be known as the St. Valentine's Day Massacre. Through a stroke of luck, Moran avoids the massacre, but knows he's been defeated.

Richard Hammond explores the extraordinary wonders of the world of detail hidden in the blink of an eye. It takes our brain around a hundred and fifty milliseconds to process what we see. We're not aware of this time lag going on, but in those few milliseconds, there are extraordinary things happening that completely pass us by. But what if we could break through this speed limit? Bend and stretch time in ways never thought possible. What new marvels would we see? Now, using the latest high-speed cameras, Richard takes us on a journey beyond our eye's limits, letting us see secrets hidden in every element of our planet. A world where thin air can shatter rock. And water can tear through metal. A world where the fastest thing on earth lies right beneath our feet. And where a spectacular celestial display is finally captured, even though many have claimed it doesn't even exist.