On July 4, 2012, scientists at the giant atom smashing facility at CERN announced the discovery of a subatomic particle that seems like a tantalizingly close match to the elusive Higgs Boson, thought to be responsible for giving all the stuff in the universe its mass. Since it was first proposed nearly fifty years ago, the Higgs has been the holy grail of particle physicists: finding it completes the 'standard model" that underlies all of modern particle physics. Now CERN's scientists are preparing for the Large Hadron Collider's second act, when they restart the history-making collider, running at higher energy--hoping to find the next great discovery that will change what we know about the particles and forces that make up our universe.

Around the world, a new generation of astronomers are hunting for the most mysterious objects in the universe. Young stars, black holes, even other forms of life. They have created a dazzling new set of super-telescopes that promise to rewrite the story of the heavens. This film follows the men and women who are pushing the limits of science and engineering in some of the most extreme environments on earth. But most strikingly of all, no-one really knows what they will find out there.

Following the Yangtze along Tiger Leaping Gorge into Yunnan in China, Palin reaches the easternmost end of the Himalayas. He gets a medical check-up before exploring medieval Lijiang with the director of the local orchestra. Heading over Myanmar to Nagaland in India he rides the steam train to Tipong Coalmine. In Assam he rides an elephant and then stays in a strange monastery.

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.

Francisco de Orellana failed to find El Dorado, but discovered the Amazon. Early in 1541, a rumor swept Quito that beyond the mountains, there lay a land richer than Mexico, or even Peru - a land of gold. The ruler of this land was so rich that he covered himself with gold dust every day and washed it off every evening. He was "the golden man", El Dorado. They had tree goals: to find La Canela, the land of cinnamon: to assess new lands for colonization; and to find El Dorado. On march 1541, They marched eastwards with more that 200 Spanish troops and thousands of native servants.

The first episode looks at how birds first took to the skies in the wake of the insects. It begins in Mexico, where Sir Attenborough observes bats being outmanoeuvred by a red-tailed hawk. Pterosaurs were the birds' forerunners, some 150 million years after dragonflies developed the means of flight, but eventually went extinct together with the dinosaurs. Birds had by then already evolved from early forms like archaeopteryx, the first creature to possess feathers. Its ancestry can be traced through reptiles, and some current species, such as the flying lizard, possibly show paths this evolution may have taken." One of the biggest birds to have ever existed was the terror bird, which proliferated after dinosaurs vanished and stood up to 2.5 metres tall. By comparison, the ostrich, while not closely related, is the largest and heaviest living bird. It was probably the evasion of predators that drove most birds into the air, so their flightless cousins evolved because they had few enemies. Accordingly, such species are more likely to be found on islands, and Sir Attenborough visits New Zealand to observe its great variety, most especially the kiwi. Also depicted is the moa, another huge creature that is now gone. The takahē is extremely rare, and high in the mountains of New Zealand, Sir Attenborough discovers one from a population of only 40 pairs. Finally, another example on the brink of extinction is the kakapo, which at one point numbered only 61 individuals. A male is heard calling — an immensely amplified deep note that can be heard at great distances from its nest.