The fourth episode starts off with the two riding through Santa Cruz, Argentina. The plan is to cross over into Chile and then going up into the Andes. Ewan and Charley head through Argentina’s red rock landscape while a member of their team copes with altitude sickness. The duo are well and truly underway and the first signs of all are well is how well the Harleys hold up in challenging conditions. The roads alternate between unforgiving and pleasant and these e-bikes push through effortlessly. As they ride through Chilean Andes, the audience is shown a picturesque view of the beauty of the countryside, an experience which Boorman calls 'magical.'

As the journey continues, there's beauty and danger in equal measure for Charley Boorman and Ewan McGrego. The duo ride their electric Harleys through the exotic and breathtaking Bolivian countryside in a tough ascent. The sixth episode showcases some of the challenges the hosts and the crew face when they scale the terrain. One of the Rivians runs into trouble while sandy roads and a heavy breeze sees Boorman take a tumble. Apart from all the accidents, the chapter also shows some quality work done by UNICEF when it comes to educating and working with the children in Bolivia.
The altitude sickness hits Taylor, their logistics man real bad and McGregor starts feeling it as well. The episode ends with a doctor heading to his hotel room to check up on him.

This remarkable science-history series investigates the blistering pace of human endeavour in space exploration, computing, energy, resources, Earth science and our understanding of the evolution of life itself. Across the last 50 years, humans have set a blistering pace and scientific discovery. We've crossed the boundaries of our solar system, made machines that can learn harnessed the power of the sun and built life from scratch. It's a period like no other in history, where human endeavour is changing everything: this is The Great Acceleration. As we race toward the future, we must examine the journey.
In the first episode, Dr Shalin Naik explores the ambitious space shuttle mission that began in the '70s plus the future colonization of Mars. Over the past 50 years, space has become central to everything, from communications to entertainment to climate modelling. And as private enterprise enters space exploration, our understanding of the universe will only continue to expand. We will know if we can survive on other objects - the moon, maybe Mars, maybe even some of the moons of Jupiter and Saturn. Deep space is the last and infinite frontier. That's what we do as human beings. We explore, we learn, we make discoveries, from the moment we're born to the moment we die.

Over the last years, the world has experienced an energy revolution, driven by an urgent need to green the grid and save life on Earth as we know it. 50 years ago, a devastating oil crisis kicked off an energy revolution. The world set course to cut the costly habit of burning fossil fuels. With the urgent new threat of a changing climate, the drive to unleash the power of the sun, earth and wind has accelerated into a race for humanity's survival. Change is taken place but, is it happening fast enough to secure our future? Technologies are right here, right now, and they will enable the transition to 100% renewables, because winning the energy race means a win for the entire world.

Across the world, rising demands for food, water and materials have pushed resources to the limit. Many parts of the world have major challenges over fresh water. A lot of soils have a lot of residual pesticides and herbicides. At the same time waste is piling higher. All this demands a new wave of innovation. The challenge is to make more of the things we need without the environmental cost.

The Blue Marble is an image of Earth taken on 1972, from a distance of about 18,000 miles from the planet's surface. It was taken by the crew of the Apollo 17 spacecraft on its way to the Moon. Before it was photographed from space, our perspective of Earth was fragmented and disconnected. Recent discoveries have revealed a dynamic and rapidly changing planet, above the crust and below.