Water plants create some of the most beautiful, bizarre and important habitats on earth. To hold on in torrents, plants use a kind of superglue. Some are armed with vicious weapons to fight titanic battles for space. Others form perfect spheres and escape from animal enemies by rolling. Where nutrients are washed away, plants turn into hunters of animals, laying traps and even counting to ensure their success.
In this episode we explore those watery worlds with David Attenborough, from Croatia to Brazil, from Colombia to Thailand, the brilliantly coloured flowers smother lakes, and in one magical river in Brazil, the water bubbles like champagne as plants create the atmosphere itself.

At the very end of East Africa's Great Rift Valley, there's a 'land that time forgot'--the rolling grasslands of the Luangwa Valley. Seemingly untouched plains teem with Africa's most iconic animals. Some are unique to this place, others are critically endangered elsewhere.
Here, prey exist in remarkable balance, each taking advantage of the secret at the heart of this Eden, the mighty Luangwa River and its dramatic annual transformation from dusty inferno to emerald paradise.

Ewan and Charley make their way to Peru from Bolivia, and the scenery is just beautiful. Ewan wanted to visit Machu Picchu since he was a kid and decides to show the world the Incan citadel set high in the Andes Mountains. Next up, they make their way to the Cutivireni, a community of Ashaninka people in the Amazon rainforest, with its carbon program to limit the magnitude or rate of global warming and its related effects.

Zachary Quinto sets out to research the strangest creatures dug up from the depths of the ocean and to see how much they lend to the monsters that are depicted in myth and legend. Starting in Australia, he meets with a teenager who was savagely attacked by a swarm of mysterious flesh-eating monsters, only to jump into the water himself the next day amongst highly venomous sea creatures.
From the carnivorous fish of American rivers to the eyeless monsters of the Atlantic Ocean, Zachary finds some merit in these old monster stories and is starting to understand just what we mean when we say that we know less than 1% of what waits in the depths below.

The last episode examines the fragile interdependence that exists between forests' wide variety of residents, including bald eagles, hunting dogs and Siberian tigers.
Over half of all the world's trees, evergreen and deciduous, stand in great assemblies. For many of us, they are places of mystery and darkness. They are key to our climate, and home to countless unique species. The boreal forest contains 750 billion trees, and it stores over 40 percent of the world's carbon, making it a vital element in the fight against climate change. In the past, we have destroyed them without hesitation. Yet, forests do have an astonishing ability to recover. If we choose to give forests time and space, they could reclothe the earth with much of the rich and varied communities of animals and plants of which we have, so recently, robbed it. A future with more forests is key to the resilience of our planet.

A new force threatens our perfect planet. In the past, five mass extinction events were caused by cataclysmic volcanic eruptions. It was not the lava or ash that wiped out life, but an invisible gas released by volcanoes: carbon dioxide. Almost every part of modern life depends on energy created by burning fossil fuels, and this produces CO2 in huge amounts. Humans are changing our planet so rapidly, it’s affecting earth’s life support systems: our weather, our oceans and the living world. The greatest change to be made is in how we create energy, and the planet is brimming with natural power that can help us do just that. It’s these forces of nature - the wind, the sun, waves and geothermal energy - that hold the key to our future.
Through compelling animal-led stories and expert interviews, we discover how CO2 is destabilising our planet. We meet rescued orphaned elephants in Kenya, victims of ever worsening droughts, and join ocean patrols off the coast of Gabon fighting to save endangered sharks. In the Amazon, we witness wildlife teams saving animals in the shrinking forests, and in San Diego we enter a cryogenic zoo preserving the DNA of endangered species before they become extinct.