In the fourth episode of the series, Commodus defeats his sister's coup but withdraws from governing, allowing others to amass power while he engages in an affair and banishes his wife.

In the fifth episode of the series, lavish imperial games at the Colosseum are highlighted by the emperor's bloody victories, but his paranoid abuses of power lead to a final betrayal.

In the last episode of the series, lavish imperial games at the Colosseum are highlighted by the emperor's bloody victories, but his paranoid abuses of power lead to a final betrayal.

Inspired by the Southern Sky as he travels Australia, Brian reveals our very latest understanding about how the Universe began & how it will end.

In the third episode, prominent adventure sports photographer Krystle Wright captures the immersive world of free-diving in Vanuatu, athletes who appear to walk on air in the canyons of Colorado, and powered para-gliders on the flooded salt pans of Utah.

Our lifespan is increasing by 2.5 years every decade - and a third of all babies born today can expect to live to 100. But living longer can come at a cost. Old age itself brings with it a range of debilitating illnesses, many of which are the result of accumulating damage during our lifetime. Three diseases in particular have become the main killers in the developed world - cancer, heart disease and dementia. But a revolution in bio-medicine is now offering new hope for the treatment of these ailments, and the potential to extend our lives still further. Methods such as gene editing and stem cell therapies are transforming the way medicine can conquer disease today. "How to Live Longer" counts with the guide of the Nobel laureate Sir Paul Nurse, for whom the big question isn't just what science can do to fix our bodies and extend our lives, but whether it's right to use all the tools and techniques available.