This programme focuses on the most famous Roman of all - Caesar. Charming, savage, power-crazed, opportunistic and brilliant, he overthrew a 500-year-old Republic and began the age of the emperors.

1917. People have had enough of the war. Behind the scenes, uprisings are brewing, like the one that toppled the Tsar in Russia; on the front soldiers begin to mutiny as they did at Chemin des Dames in France. German submarine attacks in the Atlantic will finally pull the Americans into the war, but they arrive too late to help prevent the carnage of the Battle of Passchendaele.

We all project images of ourselves online - a curated identity that defines how we want to be perceived. But what temptations exist to embellish and what are the dark implications? In this episode, enter the world of Cyberbanging, where inner city youth are using social media to brag, conspire and incite violence; two African-American women bloggers who have turned the table on the trolls who threaten them; and the creator of Abdullah X, an online character who's trying to keep Muslim kids from falling under the spell of Islamic extremists.

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.

Through the mountains and jungles of Colombia, Cooper goes in search of the truth behind one of the greatest stories ever told - the legend of El Dorado. His journey takes him from Bogota to the Caribbean coast, through territories once dominated by two cultures, the Muisca and the Tairona, who flourished for centuries before the arrival of the Spanish in the 16th century. Cooper reveals forgotten peoples who valued gold in a way the Western world still struggles to understand, travelling to an astonishing lost city and meeting the last survivors of an ancient civilisation.

A strange light in the heavens. The star that signals the birth of Jesus. Is it faith, fable, or fact? The star of Bethlehem is hard to identify thousands of years later. Can we decode the secret of the star with the science of the universe? What was it? Where did it come from? And will it return?
Discover an explanation by various astronomers and religion historians of what the star of Bethlehem really was based on available evidence.