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.

(Click CC for Subtitles) Deep in the forests of Northern Italy resides the prized white Alba truffle. Desired by the wealthiest patrons in the world, it remains a pungent but rarified mystery. It cannot be cultivated or found: the only souls on Earth who know how to dig it up are a tiny circle of canines and their silver-haired human companions-Italian elders with walking sticks and devilish senses of humor-who only scour for the truffle at night so as not to leave any clues for others. Still, this small enclave of hunters induces a feverish buying market that spans the globe.
With unprecedented access to the elusive truffle hunters, filmmakers Michael Dweck and Gregory Kershaw follow this maddening cycle from the forest floor to the pristine restaurant plate. With a wily and absurdist flare, The Truffle Hunters captures a precarious ritual constantly threatened by greed and outside influences but still somehow protected by those clever, tight-lipped few who know how to unearth the magic within nature.

April 1453. Sultan Mehmed II unleashes an artillery attack on Constantinople unlike any the world has ever known. It's the largest concentration of cannons that the world had seen in one place. The monumental task of keeping the Ottomans out of Constantinople falls on the shoulders of Genoese soldier of fortune Giovanni Giustiniani. He and his men must defend 14 miles of city walls. Mehmed launches his ambitious plans to break through the walls of Constantinople, but Giustiniani's mercenaries manage to forestall the attacks.

David Attenborough concludes his epic history of the evolution of flight with an exploration of the highly advanced fliers that dominate our skies today – the extraordinarily diverse skills of the birds, and the sonar-guided precision of the bats. He encounters some of our planet’s most remarkable fliers – from peregrine falcons dive-bombing starlings over Rome, to hummingbirds hovering in the cloud forests of Ecuador. In a spectacular finale, he visits Gomantong cave in Borneo to witness the mass exodus of a million bats.

Dive with David Attenborough into a world where a single life can last a thousand years. See things no eye has ever seen, and discover the dramatic, beautiful plant life of Earth. In the first episode, Sir David Attenborough shows how more kinds of plants are crammed together in the tropical rainforests than anywhere else on Earth. The result is astonishing beauty and intense competition - a plant battleground.
New filming techniques allow us to enter the plants’ world and see it from their perspective and on their timescale. From fast-growing trees to flowers that mimic dead animals, this is a journey into a magical world that operates on a different timescale to our own.

It's 3.5 million years ago and in East Africa a remarkable species of ape roams the land. Australopithecus afarensis has taken the first tentative steps towards humanity by standing and walking on two legs. The rift valley was forming, and the rain forests dying as Africa dried out - turning the landscape into a mosaic of scattered trees and grass. In this new environment afarensis found it more efficient to move about on two legs rather than four.