We are the generation of human beings that are going to know whether or not we're alone in the universe. This episode explores the search of exoplanets, from ancient Greek philosophers to the discoveries made possible with the Kepler Telescope. Unbelievable new worlds, planets made of diamond, planets of raining glass, worlds in collision, some plunging into stars, and others that just might harbor life.
Thanks to today's planet hunters, our views of the universe and of our place in it are undergoing one of the greatest revolutions in scientific history.

The great mountain ranges are some of the planet's most spectacular landscapes, but they are unforgiving places to live in, and only a few animals have what it takes to live at extreme altitude. Mountain animals are amongst the most elusive in the world, and this film provides unique and intimate glimpses into their secretive lives. Witness the moment four snow leopards come together when a mother and cub become trapped between two rival males. Join grizzly bears as they dance against trees to rub off their winter fur and soar with golden eagles hunting amongst Europe's snow-capped peaks.

Jungles provide the richest habitats on the planet - mysterious worlds of high drama where extraordinary animals attempt to survive in the most competitive place on earth. Flooded forests are home to caiman-hunting jaguars and strange dolphins that swim amongst the tree tops, while in the dense underworld, ninja frogs fight off wasps and flying dragons soar between trees. Acrobatic indri leap through the forests of Madagascar, while the jungle night conceals strange fungi and glow-in-the-dark creatures never filmed before.

The world's deserts are lands of extremes that force animals to come up with ingenious ways of coping with hostile conditions, giving rise to the most incredible survival stories on earth. A pride of desert lions are so hungry they risk hunting a giraffe several times their size, while male sandgrouse fly 120 miles each day to the nearest waterhole and dice with death to collect water for their chicks. Filmed for the first time, a tiny bat does battle with one of the world's deadliest scorpions, and in Madagascar, a locust swarm of biblical proportions is seen as never before.

Cities are growing at a faster rate than any other habitat on Earth. They may seem an unlikely place for animals to thrive, but they can be a world of surprising opportunity. Leopards prowl the streets of Mumbai, peregrine falcons hunt amongst New York's skyscrapers, and a million starlings perform spectacular aerial dances over Rome. In Jodhpur, langurs are revered as religious deities and in Harar, locals live in harmony with wild hyenas. Many animals, however, struggle to cope in the urban jungle. As the architects of this environment, can humans choose to build cities that are homes for both them and wildlife?

Spy in the Huddle use innovative techniques to reveal the incredible secrets of your pets' behaviour in ways never seen before. As astonishing photography explores the wild side of our playful pets, find out why hamsters love to run in a wheel, how dogs pick up the rules of the pack and how kittens learn to be solitary hunters. Featuring incredible views of plunge-diving dogs, babysitting cats, acrobatic hamsters and a playful cat outwitted by his prey" - you'll never look at your favourite companions in quite the same way again. The latest science also reveals why budgies talk, how a cat scales a vertical wall with the help of a special claw, why hamsters stuff their faces with more food than they can eat and the real meaning behind a rabbit's hop. Our pets are also given a chance to explore their wild side as we join the free-roaming pet dogs of Cusco Peru, pet rabbits living in a natural warren and the wild-living inhabitants of Cat Island, Japan. A range of innovative techniques such as moving X-rays, thermal imagery, minicam-carrying dogs and revelatory slow-motion photography shows why our pets play and how their true wild nature is just a whisker away.