We routinely talk about healthy food and clean water, but how often do we spare a thought for what enters our lungs? The World Health Organization calls air pollution the silent killer. Air pollution is proven to shorten our lifetimes and it hits the vulnerable - children, the sick and the elderly - hardest of all.
Prince William, Sir David Attenborough and astronaut Naoko Yamazaki hear the personal stories of people who are directly affected by air pollution and show us incredible solutions.

Immense shoals of fish throng our shallow seas. Small fish, in turn, sustain bigger ones. The rich coastal seas are the fishing grounds of our planet and can provide an abundance of food for wildlife and humanity. The seas fringing land make up less than a tenth of the world's oceans but 90 percent of marine creatures live in coastal waters, from fearsome sharks to lowly urchins. Protecting these habitats is a battle humanity must win.

Space colonization is no longer the fodder of science fiction, it is becoming a reality. Examine the efforts underway to establish a human colony on Mars, including how they plan to grow food, recycle wastewater and introduce greenhouse gases to revive the red planet and make it more habitable for humans. Cutting-edge computer graphics are used to bring the universe down to earth to show what life would be like on Mars, and to imagine what kind of life forms might evolve in alien atmospheres.

From space, Earth is a kaleidoscope. Turquoise plankton blooms trigger a feeding frenzy, China turns yellow with rapeseed flowers, and mysterious green lights appear in the ocean. Satellites give us a new perspective on its greatest and most beautiful spectacles allowing us to make new discoveries We can watch landscapes change through the seasons and marvel in the scale of their transformations.
Satellite cameras capture a kaleidoscope of extraordinary colours surprising and constantly changing, created by natural phenomena, by animals and by people. These colours are revealing new insight into the health of our fragile planet, transforming our understanding of our colourful home.

In this episode, Helen seeks out the colours that turned planet Earth multicoloured. To investigate the essence of sunlight Helen travels to California to visit the largest solar telescope in the world. She discovers how the most vivid blue is formed from sulfur atoms deep within the Earth's crust and why the presence of red ochre is a key sign of life. In gold, she discovers why this most precious of metals shouldn't even exist on the surface of the planet and in white, Helen travels to one of the hottest places on Earth to explore the role salt and water played in shaping planet Earth.

Earth is the most colourful place we know of. But the colours we see are far more complex and fascinating than they appear. In this series, Dr Helen Czerski uncovers what colour is, how it works, and how it has written the story of our planet - from the colours that transformed a dull ball of rock into a vivid jewel to the colours that life has used to survive and thrive". But the story doesn't end there - there are also the colours that we can't see, the ones that lie beyond the rainbow. Each one has a fascinating story to tell. Early Earth was a canvas for the vast new palette of the colours of life, with the diversity of human skin tones telling the story of how humanity spread and ultimately conquered the planet. Dr Helen Czerski explores the true masters of colour - which are often the smallest and most elusive - travelling to the mountains of Tennessee to witness the colourful mating display of fireflies, and revealing the marine creatures that can change the colour of their skin in order to hide from the world.