Lurking in the shadows of the Internet, a faceless modern-day bogeyman has attracted the attention and fear of a young generation who whisper his name online. Slenderman lives on the dark pages of the web, where impressionable youth create and cultivate his mythos in message boards, YouTube clips and various other digital incantations. But the online fairy tale becomes a shocking real-life horror as two 12-year-old girls, guided by their devotion to Slenderman, lure their friend into the woods to attempt a seemingly inexplicable, brutal murder. From the depths of one the Internet's most unsettling creations to the court case that must consider the consequences, Beware the Slenderman brings to light questions of accountability in an age where young, growing minds are only a few clicks away from creating and consuming something that may influence them to commit unspeakable crimes.

The title of Ava DuVernay's extraordinary and galvanizing documentary refers to the 13th Amendment to the Constitution, which reads 'Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States.' The progression from that second qualifying clause to the horrors of mass criminalization and the sprawling American prison industry is laid out by DuVernay with bracing lucidity. With a potent mixture of archival footage and testimony from a dazzling array of activists, politicians, historians, and formerly incarcerated women and men, DuVernay creates a work of grand historical synthesis.

Follow actor William Shatner through interviews with the other actors who have portrayed starship Enterprise captains in five other incarnations of the Star Trek franchise. Shatner's subjects discuss their lives and careers before, during and after their tenure with Star Trek. With the use of conversations and archival footage, they explore the pressures, stigmas and sacrifices that accompanied their roles and their larger careers. During the process of the film and with help from the other Captains, Sir Patrick Stewart, Avery Brooks, Kate Mulgrew, Scott Bakula and Chris Pine, Shatner overcomes his disdain and learns to embrace his best known character, Captain James T. Kirk.

In Bhutan, Palin finds himself back in the land of yaks for a last look at the high Himalaya. Trekking to Chomolhari base camp he meets a nomad with a penchant for yak songs before heading down to Paro to witness the Buddhist festival or Tsechu. In a bar in Thimphu, he discusses reincarnation and the pursuit of happiness with Benji and Khendum, two of the king's cousins, and en route to Bangladesh is taken by Benji to see the rare black-neck cranes. On his journey south through Bangladesh, Michael visits the ship-breaking beaches of Chittagong and grid-locked Dhaka. He meets a man who made a fortune in Birmingham in the poultry business, and a woman who lends money only to women. On a 1920s paddle steamer he is serenaded with the words of Bengal's Shakespeare, and he completes his epic Himalayan journey aboard a fishing boat that carries him out into the Bay of Bengal and a westering sun.

In the fourth episode, Professor Marcus du Sautoy concludes his investigation into the history of mathematics with a look at some of the great unsolved problems that confronted mathematicians in the 20th century. After exploring Georg Cantor's work on infinity and Henri Poincare's work on chaos theory, he sees how mathematics was itself thrown into chaos by the discoveries of Kurt Godel and Paul Cohen, before completing his journey by considering some unsolved problems of maths today, including the Riemann Hypothesis.

Fancisco Pizarro hoped to find great riches in the land of the Inca when he set off on his third voyage to the new world in 1527. Travel back in time with Michael Wood and learn how Pizarro ransomed the life of a king for a room full of gold and silver. Trough letter and drawings from the 16th century and film from modern-day south America, discover this remarkable story of greed, faith, dishonor and valor.