The natural world is full of colours. For us, they are a source of beauty, but for animals they are a tool for survival. David Attenborough reveals the extraordinary ways in which animals use colour: to win a mate, to fight off rivals and to warn enemies. New camera technologies - some developed especially for this series – also allow us to see colours and patterns usually invisible to human eyes.
Ultraviolet cameras reveal bright signals on a butterfly’s wings and facial markings on yellow damselfish that are used as secret communication channels. Some animals can also detect polarized light, and specialist cameras can now show us how fiddler crabs see the world, and how mantis shrimp have strange polarization patterns on their bodies to signal to a mate or rival.

The film exposes the dark world of ivory trafficking. Ivory is a prized status symbol for middle class Chinese, and poachers in pursuit of elephants in Africa are causing a great damage. Award-winning director Richard Ladkani and Kief Davidson filmed undercover for 16 months infiltrating and documenting the deep-rooted corruption at the heart of the global ivory trafficking crisis.

Horses. Powerful, graceful, and thunderously fast. No animal has made a greater impact on society or given humans more freedom and mobility. In a spectacular adventure, the film unlocks the mystery of the first horse warriors on the vast, grassy plains of Kazakhstan, where horses still roam free, and nomadic herders follow their traditional way of life.
Investigating clues from archaeology and genetics, researchers reveal vivid evidence of the very first horsemen. They also discover warriors who swept across Europe and turn out to be the ancestors of millions today.

An alarming decline in insect populations could devastate all life on earth. What's causing it, and can anything be done to stop it?
Insects are disappearing across the world. If we lost our pollinators, we would lose 80 to 90% of the plants on the planet. That is not an option. It's the ecosystems on this planet that keep humans alive. Scientists warn us that the insect apocalypse is entirely possible.

Richard Rudgley goes in search of evidence of the barbarians of the dark ages, people whose names have for 1500 years been bywords for mindless brutality. The real truth about the barbarians who marched across Europe during the Dark Ages is more shocking than what you may know. Where did they come from? Who are their descendants? Are any of their techniques and inventions still used? Richard discovers the secrets of forgotten empires, and of mighty clashes throughout Europe. The art, society and cultural legacy of the barbarians are shown to have shaped and moulded the destiny of Europe even more than the Roman Empire.
In the first part of the journey through the Dark Ages we will be tracing the legacies of the Huns, Vandals and Goths, to ask whether the 'dark ages' represent a resurfacing of much older tribal lines. Sites in Austria show how sophisticated pre-Roman communities had become with evidence of stunning craftsmanship and sophisticated farming techniques which defy the image of a mindless rabble we have come to accept without challenge.

In August of 2018, Greta Thunberg, a 15-year-old student in Sweden, starts a school strike for the climate. Her question for adults: if you don't care about her future on earth, why should she care about her future in school? Within months, her strike evolves into a global movement. Greta, a quiet Northern-European girl on the autism spectrum is now a world famous activist. The team behind Greta has been following the young activist from her very first day of school striking. The documentary shows the international crusade of Greta on in her goal to get people to listen to scientists about the world's environmental problems.