Sagan reflects on the future of humanity and the question of 'who speaks for Earth?' when meeting extraterrestrials. He discusses the very different meetings of the Tlingit people and explorer Jean-François de La Perouse with the destruction of the Aztecs by Spanish conquistadors, the looming threat of nuclear warfare, and the threats shown by destruction of the Library of Alexandria and the murder of Hypatia. The episode ends with an overview of the beginning of the universe, the evolution of life, and the accomplishments of humanity and makes a plea to mankind to cherish life and continue its journey in the cosmos. The Cosmos Update notes the preliminary reconnaissance of planets with spacecraft, the fall of the Berlin Wall and the end of apartheid in South Africa, and measures towards the reduction of nuclear weapons.

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.

Long ago, two species of human beings coexisted on Earth until competition drove one of them to extinction. This program, set in the southwest of France 35,000 years ago, reconstructs the life in the Neanderthal world at the time Cro-Magnons first entered the scene. All aspects of Neanderthal clan life are examined, including tool- and weapon-making, hunting and gathering, health and healing, childbirth, rituals, and making fire. Footage of skeletal remains and the scholarly research of eminent paleontologist Chris Stringer and Oxford University's Paul Pettitt support the documentary.

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.

One Life on the Limit is an action documentary showcasing the glamour, speed, danger and excitement of Formula One Grand Prix racing. Narrated by Michael Fassbender, the film tells the story of the golden age of Formula 1, when the sport became terrifyingly dangerous. In the late 1960s, Formula 1 cars doubled their engine size and sprouted wings, making them incredibly quick, but even more hazardous. With money pouring in from sponsorship and a new worldwide television audience, superstar drivers were born, thrown like gladiators into the ring. The drivers were legendary with charisma and raw talent, but many of them paid the ultimate price. Follow the story of the drivers who raced on the edge and those who stood up to change the sport forever. It is about the greatest show on earth, Formula 1.