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 Prohibition has recently been repealed and one of the Outfit's most important sources of income dries up.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.

In the fourth episode of the series, eyewitnesses recall how those in power at Auschwitz lined their pockets with wealth stolen from Jewish inmates while also engaging in illicit affairs.

The human eye can see extraordinary detail, but the eye of a needle held at arm's length is pretty much at the limit of our vision. Anything smaller is simply invisible, at least to the naked eye. But what if we could see this hidden world all around us in greater detail and magnification than ever before? How different would our familiar surroundings then seem? Richard Hammond explores the astonishing miniature universe all around us, revealing that small is not only beautiful, it can also be very, very powerful. From seeing the microscopic changes to ice crystals that can trigger an avalanche to watching in horror the invisible aftermath of a sneeze on a commuter train and learning how the surface of an ordinary-looking plant hides an astounding secret that will make walking on the moon safer, Richard harnesses cutting-edge technologies to transport the viewer into a spectacular micro realm.

Chris Lintott and Maggie Aderin-Pocock report on the reaction to the dramatic announcement of the discovery of phosphine gas in the clouds of Venus, a gas that could be a sign of life. Venus remains an inhospitable and unlikely host. But if not Venus, where in the solar system is the best place to look for alien life? Chris and Maggie investigate the latest missions to Mars and the icy moons of Jupiter and Saturn. Away from the search for life, Pete Lawrencepreviews the best meteor showers of the year.

From the detection of gravitational waves generated in space over a billion years ago, to discoveries in genetics here on Earth, we've collected the most compelling science breakthroughs and advances of 2016. Thanks to magnificent, hard-working scientists and researchers around the world, science keeps marching ever forward. And this year saw some discoveries that are absolutely brimming with the promise of greater discoveries, breakthroughs and quality of life in the future.

Take a look back at many of the most fascinating science stories of 2017, a year full of stunning advancements in individual fields of study, from astronomy to biology, geology to history – when we piece these discoveries together we see the year in a new light.