Cannabis is the world's favourite drug, but also one of the least understood. Can cannabis cause schizophrenia? Is it addictive? Can it lead you on to harder drugs? Or is it simply a herb, an undervalued medicine? Addiction specialist Dr John Marsden discovers that modern science is finally beginning to find answers to these questions. John traces the cannabis plants' birthplace in Kazakhstan; finds the origins of our sensitivity to cannabis in the simple sea squirt; and finds out just what it does to our brains. He meets people who have been changed by this drug in drastically different ways - from those whose lives have been shattered to those who lives have been revived.

The extraordinary wildlife, culture and history of this immense, fascinating ocean and its myriad islands are revealed in stunning detail. With its coral reefs, turquoise lagoons and dramatic oceanic atolls, the South Pacific is the archetypal paradise. It is still relatively healthy and teeming with fish, but it is a fragile paradise. International fishing fleets are taking a serious toll on the sharks, albatross and tuna, and there are other insidious threats to these bountiful seas. We look at what is being done to preserve the ocean and its wildlife.

Art critic Andrew Graham-Dixon tells the incredible story of Russian art, its mystery and magnificence and until now a story untold. He explores the origins of the Russian icon from its roots in Byzantium and the first great Russian icon, Our Lady of Vladimir to the masterpieces of the country's most famous icon painter, Andrei Rublev. Both epic and awe-inspiring, and producing brilliant art", nevertheless medieval Russia could be a terrifying place. Criss-crossing the epic landscape, Andrew visits the monastery founded by Ivan the Terrible, where his favourite forms of torture found inspiration in religious art. One man would shine a light into Russia's 'dark' ages - Peter the Great who, surprisingly, took as his inspiration Deptford in South London.

Andrew Graham-Dixon explores how Russia changed from a feudal nation of aristocratic excess to a hotbed of revolution at the beginning of the 20th century and how art moved from being a servant of the state to an agent of its destruction. From monuments that celebrate the absolutism of the tsars to the epic Russian landscape as inspiration; from the design and construction of gold and glittering palaces to the minutiae of diamond-encrusted Faberge eggs; and eventually to the stark and radical paintings of the avant-garde, the journey through Russian art history is one of extraordinary beauty and surprise.

The final part examines political revolution and how art was at the forefront of throwing out 1,000 years of royal rule, from its earliest revolutionary days of enthusiasm and optimism when painting died, the poster was king and the machine-made triumphed over the handmade to the dead hand of Socialist Realism. Andrew roots out great portraits of Stalin now hidden in museum storerooms and never on public view, looks at the transformation of the Moscow metro into a great public art gallery and visits the most stunning creation of post-war Communist rule, the Space Monument. Finally, he comes to the confusion and chaos of Russia today and how it is producing some of the world's strangest art - from heroic sculptures of Russian leader Vladimir Putin to the insides of a giant erotic apple; from the recreation of the Imperial royal family facing the firing squad to sculpture in liquid oil; from Russia's embrace of the commercial art market to a return to Socialist Realism. Russia seems to stand on another brink of revolution.

Andrew Graham-Dixon retraces Vasari's footsteps for this captivating two-part film in a short Art of Italy season. He's an enthusiastic guide, lapsing easily into Italian conversation with the custodians of galleries and chapels who allow him a private view. From Brunelleschi's Duomo in Florence to less familiar marvels - a Donatello sculpture; Masaccio frescoes - he illustrates how rapidly ideas developed. A final treat for him - and us - is a tour of the Vasari Corridor, a rarely accessed gallery that zigzags across the Florentine rooftops.