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.

The architectural design of Beijing's ancient complex of palaces and temples enabled it to survive centuries of earthquakes. The Forbidden City is the world’s biggest and most extravagant palace complex ever built. For five centuries, it was the power center of imperial China and survived wars, revolution, fires, and earthquakes. How did the Ming Emperor’s workforce construct its sprawling array of nearly 1,000 buildings and dozens of temples in a little over a decade?

Helen Czerski ventures beyond the visible spectrum in the final (and best) episode in this vibrant series, showing how electromagnetic radiation is so much broader than the narrow slice of reality we see with our eyes. Before delving into the details of UV, infrared and x-rays, Dr Czerski explores colour subjectivity by trying on a dress that recently divided the internet — to some it appeared blue and black, to others white and gold. It's a perfect fit. It's also a neat analogy of how people can have opposing views but both swear blind that their perspective is correct. The series ends with some amazing imaging techniques that show our bodies in a whole new light.

Beginning with the origins of the universe in the Big Bang, Sagan describes the formation of different types of galaxies and anomalies such as galactic collisions and quasars. The episodes moves further into ideas about the structure of the Universe, such as different dimensions (in the imaginary Flatland and four-dimensional hypercubes), an infinite vs. a finite universe, and the idea of an oscillating Universe (similar to that in Hindu cosmology). The search into other ideas such as dark matter and the multiverse is shown, using tools such as the Very Large Array in New Mexico. Cosmos Update shows new information about the odd, irregular surfaces of galaxies and the Milky Way perhaps being a barred spiral galaxy

Across the universe, galaxies are going dark, and scientists don't know why the stars are losing their shine. Something is slowly drawing the curtains closed on the universe. Our milky way is under threat. Astronomers race against time to uncover the truth behind how galaxies are born and how they die before all of the lights go out.

Stone opens the episode on Vietnam with a review of American intervention in Latin America. Lyndon Johnson, according to Stone, disregarded JFK’s “memo” about withdrawing troops and instead escalated. The Cataclysm in Vietnam as the war reaches a turning point - there's no going back. The betrayal by Richard Nixon.