Prepare yourself for an unparalleled sensory experience. Samsara reunites director Ron Fricke and producer Mark Magidson, whose award-winning films Baraka and Chronos were acclaimed for combining visual and musical artistry. Samsara explores the wonders of our world from the mundane to the miraculous, looking into the unfathomable reaches of humanity's spirituality and the human experience. Neither a traditional documentary nor a travelogue, Samsara takes the form of a nonverbal, guided meditation.

Fourth episode examines how plants either share environments harmoniously or compete for dominance within them. Attenborough highlights the 1987 hurricane and the devastation it caused. However, for some species, it was that opportunity for which they had lain dormant for many years. The space left by uprooted trees is soon filled by others who move relatively swiftly towards the light. The oak is one of the strongest and longest-lived, and other, lesser plants nearby must wait until the spring to flourish before the light above is extinguished by leaves. Tropical forests are green throughout the year, so brute force is needed for a successful climb to the top of the canopy: the rattan is an example that has the longest stem of any plant. As its name suggests, the strangler fig 'throttles' its host by growing around it and cutting off essential water and light. Some can take advantage of a fallen tree by setting down roots on the now horizontal trunk and getting nutriment from the surrounding moss and the fungi on the dead bark. The mountain ash (eucalyptus regnans) grows so tall, that regeneration becomes a considerable problem. It is easily flammable, so its solution is to shed its seeds during a forest fire and sacrifice itself. It therefore relies on the periodic near-destruction of its surroundings in order to survive. Attenborough observes that catastrophes such as fire and drought, while initially detrimental to wildlife, eventually allow for deserted habitats to be reborn.

Ripped from international headlines, The Hacker Wars takes you to the front lines of the high-stakes battle over the fate of the Internet, freedom and privacy". Get ready to be shuttled between story lines at lightning speed mirroring the disjointed lives of the protagonists and life on the Internet. The Hacker Wars- a film about the targeting of (h)ac(k)tivists and journalists by the US government. Hacktivists are either terrorists or freedom fighters depending on ones perspective on who should control information. Meet weev, infamous hacker; Barrett Brown, journalist and propagandist for the hacktivist collective, Anonymous; and Jeremy Hammond, aka Anarchaos, number one on the FBI's cyber-criminal list. The fourth character is Sabu, the uber-hacker turned FBI informant who ran the FBI's cyber unit for 9 months and is responsible for many arrests. He is the shadowy protagonist in a high-stakes game of espionage and betrayal in the age of the Internet. Barrett Brown, American journalist, is facing 105 years in prison for publicizing information revealed through Jeremy Hammond's epic hacks. Hammond himself has just begun a 10-year prison term. Andrew Auernheimer, known by his hacker handle weev embarrasses large corporations. He was sentenced to 41 months for hacking AT&T, but his conviction was just overturned. He vows to continue doing what landed him in prison in the first place. These hacktivists are the rock stars of the Internetmodern-day folk heroes. Glenn Greenwald (Snowdon Leaks), Pulitzer Prize-winning journalist and others explain why these anti-heroes exposing the security surveillance state are essential to a functioning democracy.

Is God worshipped in other worlds, across the cosmos? How might alien deities differ from our own? The answer may lie buried on Earth. Animal behaviorists are testing elephants and finding them capable of having spiritual thoughts. Artificial intelligence researchers are building enlightened robots that contemplate the divine. Meanwhile, cosmologists are looking for universal equations that could replace God. Have advanced aliens discovered everything there is to know about the universe? Or are they looking to a higher power for answers?

The Cave of Swallows in Mexico is a 400m vertical shaft, deep enough to engulf the Empire State Building. The Lechuguilla cave system in the USA is 193km long and 500m deep with astonishing crystal formations hanging from its chambers. Although often overlooked, caves are remarkable habitats with equally bizarre wildlife. Cave angel fish cling to the walls behind cave waterfalls with microscopic hooks on their flattened fins. Cave swiftlets navigate by echo-location and build nests out of saliva. The Texas cave salamander has neither eyes nor pigment. Unique access to a hidden world of stalactites, stalagmites, snotites and troglodytes brings a wealth of surprises.

Is mankind alone, or are there aliens out there, either waiting to be discovered, or on their way to find Earth? Professor Brian Cox spends this episode asking such questions, and what he discovers may raise a few eyebrows. He begins by exploring the human race's efforts to find neighbours in outer space, including the launch of two golden discs containing a greeting from Earth in the 1970s; they are still travelling and are now the most distant man-made objects from the planet. Brian also meets members of the Search for Extra-Terrestrial Intelligence, who have been monitoring radio signals for 50 years without success, before discussing the ingredients needed to make an intelligent civilisation with astrophysicist Dr Frank Drake.