Humanity is under threat - from storms that seem to get ever fiercer, earthquakes that seem ever more deadly, and killer viruses that are engulfing the globe. Some scientists think it's time for us to fight back. Can we - should we -hack the planet?

Once life arrived in the Galapagos, it exploded into unique and spectacular forms. David Attenborough investigates the driving forces behind such evolutionary innovations. We learn that life must be able to adapt quickly in these ever-changing volcanic landscapes. It has resulted in species found nowhere else in the world, such as giant whale sharks and marine iguanas that can spit sea-salt from their noses, dandelion seeds that grow into tree-sized plants and spiders that can blend perfectly into the darkness. Adaptation has been the key to survival in these islands so far, but the story of life in the Galapagos doesn’t end here. The catalyst that triggers these explosions of life remains in place.

No two islands in the Galapagos are the same. The imperceptible drift of a continental plate keeps each island biologically isolated. David Attenborough explores this evolutionary crucible, encountering tortoises that weigh up to half a tonne, finches that use tools and lizards that communicate using press-ups; for Darwin, this was all evidence for his theory of evolution. We see the final footage of the world famous tortoise fondly known as Lonesome George, the last survivor of his species. David Attenborough was the last person to have ever filmed with him. Darwin’s famous visit had a downside – the arrival of man. David investigates the impact we’ve had in these islands, as our influence is a double-edged sword. We’ve disrupted the natural balance but he also believes Darwin would be thrilled with the advances we have made in science. We’re also now uncovering evidence that evolution is more rapid than Darwin could ever have imagined. Whatever wonders the Galapagos Islands hold today, they are only a hint of what awaits them in the future.

In the second episode, filmmaker Martin Scorsese examines the life of musician George Harrison, weaving together interviews, concert footage, home movies and photographs.

The film chronicles Allen's career - from teen writer to Sid Caesar's TV scribe, from stand-up comedian to award-winning writer-director averaging one film-per-year for more than 40 years. Exploring Allen's writing habits, casting, directing, and relationship with his actors first-hand, new interviews with A-listers, writing partners, family and friends provide insight and backstory to the usually inscrutable filmmaker.

This is one of the most ambitious animated programmes ever attempted for broadcast TV, recreating every detail of these extraordinary animals in an entirely digital production that stretches the boundaries of broadcast 3D with a scale and ambition normally reserved for Hollywood feature films. Planet Dinosaur 3D is a thrilling and immersive journey into a lost world. Pulling together cutting edge research from around the world this programme uses the latest, stunning fossil evidence to chart the rise and fall of the 'Ultimate Killers'; from the iconic Spinosaurus, the largest predator ever to walk the Earth, to Microraptor and the feathered, flying dinosaurs from China. At last, thanks to the advances in technology, and for the first time ever, these monsters can be experienced in all their full, magnificent wonder.