Scientists genuinely don't know what most of our universe is made of. The atoms we're made from only make up four per cent. The rest is dark matter and dark energy (for 'dark', read 'don't know'). The Large Hadron Collider at CERN has been upgraded. When it's switched on in March 2015, its collisions will have twice the energy they did before. The hope is that scientists will discover the identity of dark matter in the debris. The stakes are high - because if dark matter fails to show itself, it might mean that physics itself needs a rethink.

Garrett McNamara recovers from the injuries he sustained at Mavericks and begins training to return to Nazaré for another season. While surfing at Indonesia's G-Land site, Garrett suffers more injuries that threaten to take him off the waves permanently. Meanwhile, a friend of Garretts catches an 80-foot wave at Nazaré, taking the world record from McNamara. McNamara resolves to continue his hunt for a 100-foot wave.

Deep in the jungles of Taiwan lives female giant golden orb-weaver spider -- among the biggest web building spiders on the planet. With a leg-span of almost eight inches and silk like kevlar, she's a fearsome predator. But the orb spiders must find a way to mate with her male counterparts, who are approximately 10 times smaller and 500 times lighter than she is.

The Internet enables us to connect with people, images and information in ways that were unimaginable 30 years ago. But with every click we are re-wiring the physical structure of our brains. Are we evolving or actively de-evolving down a dopamine-laced click-hole? In this episode meet a 17-year-old boy struggling with an addiction to online pornography; autistic technologists in Silicon Valley who are turning their genetic variation to an advantage; plus, Nootropics, a class of cognition-enhancing supplements that claims to rewire the brain.

Documentary telling the little-known story of how Darwin came to write his great masterpiece, On the Origin of Species, a book which explains the wonderful variety of the natural world as emerging out of death and the struggle of life. In the twenty years he took to develop a brilliant idea into a revolutionary book, Darwin went through a personal struggle every bit as turbulent as that of the natural world he observed. Fortunately, he left us an extraordinary record of his brilliant insights, observations of nature, and touching expressions of love and affection for those around him. He also wrote frank accounts of family tragedies, physical illnesses and moments of self-doubt, as he laboured towards publication of the book that would change the way we see the world.

In a far cry from the steamy jungles of Rwanda or the icy waters of the Arctic, British naturalist Sir David Attenborough has donned a necktie and met with US president Barack Obama to discuss climate change and the future of the planet. The two met at the White House — a place the naturalist had never yet explored — on Sir David's 89th birthday in May to film the interview". It was the first time the respected wildlife filmmaker had met an American president and he seemed a little awed by the experience. Mr Obama, who grew up watching Sir David's programs, seemed equally thrilled. The president has the environment and climate change on his radar and is anxious to see progress made as his presidency comes to a close. He faces stiff opposition from Republicans in Congress on his plans to tackle climate change, but remains determined to make changes before leaving office. "I don't have much patience for anyone who denies that this challenge is real," he said. "We don't have time for a meeting of the Flat Earth Society." Sir David, who has been called "the godfather of natural history TV" by the BBC, brought to the meeting six decades dedicated to sharing the wonders of the natural world with television audiences. After initially being rejected for television because his teeth were deemed "too big", Sir David went on to make his Life on Earth television series, which has been watched by more than 500 million people worldwide. His name is now synonymous with nature, conservation and wildlife. During the television interview, the men discussed global warming, renewable energy and how children and young people hold the key to reversing the damage.