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 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.

This episode explores what can give brains a boost. In America, Angela tries out a new treatment that's proven to help memory and concentration. In Japan, a remarkable 100-year-old reveals the colourful foods that keep minds more active. Plus Chris discovers the best exercise we can do for our brains. At the cutting-edge of science, discover how injections of young people's blood may help beat dementia.

The world of the armoured creatures is equally fascinating and bizarre. Galapagos giant tortoises solve the problem of making love in a suit of armour; a heated sea turtle orgy leaves females in mortal danger and we witness the explosive arrival of a baby pig-nosed turtle. Giant salt-water crocodiles crowd a flooded river-run to fish for mullet and a caiman leads her brood in a touching trek to a communal crèche.

After becoming the most powerful mob boss in the country, Al Capone now finds himself locked up in America's newest and harshest maximum security prison: Alcatraz. Prohibition has recently been repealed and one of the Outfit's most important sources of income dries up. With Capone cut off from all communication, his most trusted men, Frank Nitti, Tony Accardo and Paul Ricca, must keep his organization from collapsing. With Americans flocking to theaters by the thousands, the movie business is raking in millions of dollars a month. To take advantage of Hollywood, Nitti recruits Willy Bioff. Acardo breaks into a new racket in Chicago: slot machines. With help from Ricca, Accardo builds a network of slots in Chicago bars, earning up to $20,000 a year. By the end of 1939, the Outfit is bringing in more money than ever before... But new problems start to appear.

Mid-1942, as Hitler’s forces are pushing into southern Russia to take the oilfields, he spies a city prized by his enemy Stalin – Stalingrad. If Hitler can capture this city, he can expand his empire all the way to the Urals. But what Hitler hasn’t counted on is the enormous resilience of the Soviet people; men and women willing to defend their Motherland at all costs.
What ensues at Stalingrad is one of the bloodiest battles in the history of warfare, with an estimated 2 million total casualties, and an event that turns the tide for the Germans.