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.

This series illuminates unique and bizarre evolutionary journeys that have brought forth some of the world’s most impressive animals. We unearth a 50-million-year-old mystery mammal sought out a new source of food in the water, starting a spectacular evolutionary journey so that today it looks like a fish. How did a creature built for land become master of the ocean?

David Attenborough discovers the plants that have evolved to shed their dependency on water enabling them to survive in the driest environments. The story begins at midnight in midsummer as David steps into the Princess of Wales Conservatory to witness the extraordinary nocturnal blooming of a cactus. The queen of the night, with its giant flowers, is the centre piece of a stunning symphony of cacti blooms that burst open in the desert (and at Kew) at night. In a mesmerizing 3D slow motion sequence, we discover the extraordinary connections between cacti and their natural pollinators: bats. As the sun rises, David meets other amazing plants. Species like the century plant, the Agave franzosini, which grows steadily for over 50 years, only to then flower itself to death with one mighty telegraph pole sized bloom which literally bursts out of the roof of Kew’s green house.

Explore the latest science behind the headlines and the coolest scientific developments that impact our lives. Technology catapults to new heights in 2015, going faster and further than ever before. We have canvassed the world in search of the best and most fascinating science and tech stories of the year for 2015 YEAR IN SCI-TECH". This action-packed hour of fun and intrigue revisits the world’s first glimpse of Pluto and images of water on Mars while exploring what this all could mean for intelligent life in the universe – all while earthling’s inch closer to becoming actual space tourists. Throughout the hour, we revisit the year’s most amazing techological feats and scientific discoveries, including new and elusive animal species discovered deep under the ocean, as well as the hottest tech trends – from hover boards to driverless cars and trucks, and the newest advances in mind-blowing virtual reality.

The human brain is the most complex object we’ve discovered in the universe, and every day much of its neural circuitry is taken up with the tens of thousands of decisions we need to make. ‘How do I decide?’ is a journey through the unseen world of decisions, and how they get made. Decisión-making is what allows us to navigate a course through life. Discover how important emotions are in making decissions and, as we learn more about our own brains, we can break away from slavery to our impulses. Neuroscience shows that you're made up of multiple competing drives and by understanding how choices battle it out in the brain, we can learn how to make better decisions.

When we look up into the sky it appears we live in a universe that is filled with light. But scientists are now certain there is far more matter in the dark portions of our universe that we can’t see or touch. There’s something hiding in the shadows. Cosmologists agree that 'dark matter' has helped shape our Universe, but now they need to figure out what dark matter is. What’s going on in this hidden world? Could it have formed its own dark stars, planets, and even life forms? Could this Shadow Universe threaten our world of light?