The second episode of the series looks at dreams and tries to explain what happens in the brain and body after we go to sleep. It looks at the significance of dreams and what dreams can teach us about ourselves. It talks to neuroscientists who discuss slow-wave sleep and REM (rapid eye movement) sleep during which dreams occur. It looks at the history of dream interpretation and its validity.

Ever wonder what's happening inside your head? From dreaming to anxiety disorders, discover how your brain works with this illuminating series. The first episode looks at how memory works and examines the way in which the brain stores, processes, and retrains memories. It also looks at the ways in which memory can fail and discusses how memories can warp over time. It talks to neuroscientists and a memory champion who explains her techniques.

Hours before Mehmed II launches his final assault, an ominous sight shakes both sides. Rumors of a 40-ship fleet's imminent arrival have swirled for weeks, but it's exact whereabouts remained unknown. Ottoman cannons reduced the city walls to rubble, and Venetian reinforcements arrived too late. The conquest of Constantinople ushers in a new era for the Ottoman Empire, being a dominant force in world politics for 300 years. Mehmed II, in many senses, changed the nature of world history.

The fiercest, strangest, and wildest creatures in the animal kingdom face off in a countdown of the most incredible animal moments ever recorded. Across arid deserts, through dense rainforests, and into the deepest of oceans, witness remarkable scenes of animal activity, from deadly showdowns to wild romances.

To celebrate the 30th anniversary of its launch, this film tells the remarkable story of how the Hubble Space Telescope revealed the awe and wonder of our universe and how a team of daring astronauts risked their lives to keep it working.
Additionally, a team led by Greg Bacon and Dr Frank Summers has transformed many of Hubble's most awe-inspiring images into visualisations - from the spectacular Orion Nebula to the fabulous Whirlpool Galaxy and ethereal Horsehead Nebula. One of the most mind-blowing of the visualizations takes the viewer on a remarkable journey, flying across the Universe to witness almost 13 billion years of cosmic evolution. It's called the 'Hubble Ultra Deep Field' and was created when Hubble stared at a small patch of sky for the equivalent of more than 11 days to see some of the most distant galaxies ever observed.

Why do we sleep? And what does sleep have to do with memory, trauma, and our emotions? From fruit flies to whales, virtually every animal sleeps. But why? Why do we need to spend nearly a third of our lives in such a defenseless state? Scientists are peering more deeply into the sleeping brain than ever before, discovering just how powerful sleep can be, playing a role in everything from memory retention and emotional regulation to removing waste from our brains. So why are we getting so little of it?