Professor Jim Al-Khalili discovers the intriguing story of how we discovered the rules that drive the universe. Energy is vital to us all, but what exactly is energy? In attempting to answer this question Jim investigates a strange set of laws that link together everything from engines to humans to stars. It turns out that energy, so critical to daily existence, actually helps us make sense of the entire universe.

Professor of physics Jim Al-Khalili investigates the most accurate and yet perplexing scientific theory ever - quantum physics, the perplexing theory of sub-atomic particles. Turning his attention to the world of nature, can quantum mechanics explain the greatest mysteries in biology? The European robin navigates using one of the most bizarre effects in physics - quantum entanglement, a process which seems to defy common sense. Jim finds that even the most personal of human experiences - our sense of smell - is touched by ethereal quantum vibrations. According to new experiments it seems that our quantum noses are listening to smells. Jim discovers that the most famous law of quantum physics - the uncertainty principle - is obeyed by plants and trees as they capture sunlight during the vital process of photosynthesis. Jim wonders if the strange laws of the sub-atomic world, which allow objects to tunnel through impassable barriers in defiance of common sense, could effect the mechanism by which living species evolve?

The Nazca Lines of Peru have been an important part of the Ancient Astronaut theory since its beginning. Originally Von Daniken claimed that the lines were kind of a UFO runway, or a type of alien airport, where the alien craft landed and took off. The idea that it was an airport makes no logical sense, and the symbols and rituals which were a huge part of the Nazcan culture more than explain the so called Nazca lines.

Austrian director Michael Glawogger travels to five countries to focus on some of the worst jobs imaginable: Ukrainian miners crawl into tiny cracks in old coal pits to scratch out a few bags of winter fuel; Indonesian workers trudge long distances carrying baskets with hundreds of pounds of sulfur chunks extracted from a steaming mountain; Pakistanis risk explosions and burial under tons of scrap iron as they dismantle huge carrier ships. The visuals are everything here. Despite the hardships depicted, many sequences have a dreamlike beauty. In addition, the director has a bone-dry sense of irony; during the Ukraine scenes, he frequently cuts away to a statue of Stakhanov, the "hero" lauded by the Soviets for his superhuman work habits. He also shows us an old German smelting works that's been converted into a theme park.

Take another walk on the wild side with our favourite pets. Extraordinary photography reveals their hidden senses and secret communication skills. Dogs take a car trip through Paris, using their legendary sense of smell to show us a very different city. A hamster uses his remarkable senses to stage a great escape and then deploys more navigational talents to find his way home. Cats become intoxicated on the scent of a plant and suffer the consequences. A budgie shows his hidden charms to his mate as, under UV light, his crown and cheeks positively glow. Goldfish reveal secret senses that can detect the slightest water movement. A guinea pig gives birth and the newborns receive surprising care from their father. In South America, where guinea pigs have lived with people for 7,000 years, they express the true meaning of their entertaining calls. When we groom a horse we speak their language, but horses use ears to communicate in ways that we are rarely aware of. In Japan cats show their secret messages and in Peru dogs reveal the hidden signs that allow them to communicate across a city. Packed with extraordinary facts and wild behaviour - you'll never look at your pet in the same way again

Time is woven into the fabric of the universe as one of the dimensions in which we live our daily lives. But maybe it is only a brain state that we use to piece together events. Could it exist only in our minds? Your sense of time can be totally different than the person next to you. This and other theories illustrate that time is an illusion and does not really exist. The world's top physicists tackle this fundamental question, does time exist, and offer new ways to perceive the physical world.