Iain explores man's relationship with fire. He begins by embarking on an extraordinary encounter with this terrifying force of nature - a walk right through the heart of a raging fire. Fire has long been our main source of energy and Iain shows how this meant that the planet played a crucial role in Britain's industrial revolution, whilst holding China's development back. Along the way he dives in a mysterious lake in Oregon, climbs a glacier of salt, crawls through an extraordinary cave in Iran and takes a therapeutic bath in crude oil.

The little known story of our quest to understand the origins of the Moon. Neil Armstrong's "giant leap for mankind" began a scientific journey of discovery that lead to one of the most startling conclusions in the history of astronomy. The Moon was born from Earth.

the final episode deals with plants that live in hostile environments. Attenborough visits Ellesmere Island, north of the Arctic Circle, to demonstrate that even in a place that is unconducive to life, it can be found. Algae and lichens grow in or on rock, and during summer, when the ice melts, flowers are much more apparent. However, they must remain close to the ground to stay out of the chilling wind. In the Tasmanian mountains, plants conserve heat by growing into 'cushions' that act as solar panels, with as many as a million individual shoots grouped together as one. Others, such as the lobelia in Mount Kenya, have a 'fur coat' of dense hairs on their leaves. The saguaro cactus in the Sonoran Desert flourishes because of its ability to retain vast amounts of water, which can't be lost through leaves because it has none. Many desert dwellers benefit from an accelerated life cycle, blooming rapidly within weeks after rainfall. Conversely, Mount Roraima is one of the wettest places on Earth. It is a huge sandstone plateau with high waterfalls and nutrients are continuously washed away, so plants have to adapt their diet if they are to survive. A bladderwort is shown invading a bromeliad. Inhabitants of lakes have other problems to contend with: those that dominate the surface will proliferate, and the Amazon water lily provides an apt illustration. Attenborough ends the series with an entreaty for the conservation of plant species.

Professor Jim Al-Khalili sets out to discover whether nuclear power is safe. He begins in Japan, at the former Fukushima nuclear plant, where he meets some of the tens of thousands of people who have been evacuated from the exclusion zone. He travels to an abandoned village just outside the zone to witness a nuclear clean-up operation. Jim draws on the latest scientific findings from Japan and from the previous explosion at Chernobyl to understand how dangerous the release of radiation is likely to be and what that means for our trust in nuclear power.

Roses are red, violets are blue but according to the latest understanding these colours are really an illusion. One that you create yourself. Horizon reveals a surprising truth about how we all see the world. You may think a rose is red, the sky is blue and the grass is green, but it now seems that the colours you see may not always be the same as the colours I see. Your age, sex and even mood can affect how you experience colours. Scientists have unlocked the hidden power that colours can have over your life - how red can make you a winner, how blue makes time speed up. Watch an experiment where for people in a blue pod, a minute lasts 11 seconds shorter.

Professor Jim Al-Khalili discovers the intriguing story of how we discovered the rules that drive the universe. Energy is vital to us all, but what exactly is energy? In attempting to answer this question Jim investigates a strange set of laws that link together everything from engines to humans to stars. It turns out that energy, so critical to daily existence, actually helps us make sense of the entire universe.