When we look up into the sky it appears we live in a universe that is filled with light. But scientists are now certain there is far more matter in the dark portions of our universe that we can’t see or touch. There’s something hiding in the shadows. Cosmologists agree that 'dark matter' has helped shape our Universe, but now they need to figure out what dark matter is. What’s going on in this hidden world? Could it have formed its own dark stars, planets, and even life forms? Could this Shadow Universe threaten our world of light?

The third episode is devoted to the ways in which plants reproduce. Pollen and a stigma are the two components needed for fertilisation. Most plants carry both these within their flowers and rely on animals to transport the pollen from one to the stigma of another. To do this, they attract their couriers with colour, scent and nectar. It isn't just birds that help pollination: some mammals and reptiles also do so. However, it is mostly insects that are recruited to carry out the task. To ensure that pollen is not wasted by being delivered to the wrong flower, some species of plant have developed exclusive relationships with their visitors, and the gentian and its attendant carpenter bees is one example. Since pollen can be expensive to produce in terms of calories, some plants, such as orchids, ration it by means of pollinia and a strategically placed landing platform. Other orchids offer no reward for pollination, but instead mislead their guests by mimicking their markings and aroma, thus enticing males to 'mate' with them (Pseudocopulation). The most extreme fertilisation method is one of imprisonment, and one plant that uses it is the dead horse arum. It is often found near gull colonies, and mimics the appearance and smell of rotting flesh. Blow-flies are attracted to it, and are forced to stay the night before being allowed to depart in the morning, laden with pollen. Finally, Attenborough introduces the world's largest inflorescence: that of the titan arum.

Earth’s oceans help make our planet different from every other planet in the solar system. As far as we know, no other place is the right temp for liquid water, the most essential ingredient for life to exist. The oceans are Earth’s primary stabilizing force, and their immense power helps to shape the appearance and behavior of the entire planet and everything living on it. And they are also the planet's great unknown - their deepest points have been visited less than the surface of the moon.

What are the latest discoveries in the deadly world of asteroids? Will a recently returned Japanese spacecraft become the first to bring an asteroid sample back to our planet? What would happen to America's East Coast if the massive asteroid impact that helped form Chesapeake Bay 35 million years ago struck today? And why did President Barack Obama choose an asteroid as the destination for the next great manned mission into space? Learning about these huge space rocks isn't just about science, it's about survival.

What's your idea of the perfect birth? Do you want every medical intervention known to science or do you want to go it alone, without the help of a doctor or midwife? And what about after birth? Perhaps you'll hang on to your baby's placenta and carry it around with your newborn until it dries and drops off naturally? Or maybe you'll decide to eat it by whizzing it up into a smoothie? This film follows four pregnant women all making very different choices around their births, all determined to do it their way." 37-year-old Jo plans to deliver her baby completely alone on board her barge, without the assistance of any medical professional. By contrast, 34-year-old Anna is opting to sidestep the pains of labour and book in for a c-section at the Portland Hospital in London. Anna wants all the medication available and she doesn't want to feel a thing. There are plenty of unusual plans for after the birth too. In Devon, 33-year-old Lisa plans to lotus birth - she'll leave her baby's umbilical cord attached to its placenta and she'll keep it fresh by dusting it with salt, rose petals and lavender oil. 35-year-old Kati from Manchester is going to whizz her afterbirth into a smoothie and consume it over a number of days. She hopes it will help her stave off post-natal baby blues and bounce back as quickly as possible. Fending off bewildered looks and concerns from friends, family and medical professionals, each woman is going against convention to have the birth she wants. There are free and frank discussions between mums and daughters and decisions to go against medical advice. So does breaking with the norm and sticking to your guns pay off? And what really is the perfect birth?

Tom Service plunges into the life and times of Mozart to try and rediscover the greatness and humanity of the living man in his moment. Mozart's prodigious output and untimely death have helped place him on a pedestal that can often blind us to the unique brilliance of his work in the context of his life and times. Service visits the key cities and rooms in which Mozart lived and worked, plays some of Mozart's original instruments and scores, and gradually uncovers the brilliance and originality of his work." There is the prodigious childhood when Mozart was feted as an infant phenomenon around Europe's most glittering courts, and his golden decade in Vienna in which masterpiece followed masterpiece - operas, symphonies, piano concertos, string quartets - as if this short, high-voiced man-child must have been taking dictation from some divine source, until his death at the age of just 35 in 1791. Even more than the music, Mozart's tragic demise sets the seal on his myth. The trajectory of Mozart's life sets the template for the romantic paradigm whose throes we are still in today, which requires our creative heroes to die young to prove that they were too good for this madding world, whether it be Wolfgang Amadeus or Jimi Hendrix. Service travels from London to Vienna and Salzberg, unpicking the living, breathing genius that was Mozart. With Sir John Eliot Gardiner, Nicola Benedetti, Paul Morley and others.