From unexplained flashes in the night sky to flying saucers, this episode delves into the mysterious world of UFOs. How our drive to explain these bizarre phenomena, and desire to discover little green men, has in fact transformed our understanding of the universe

Horizon uncovers the secret world of our dreams. In a series of cutting-edge experiments and personal stories, we go in search of the science behind this most enduring mystery and ask: where do dreams come from? Do they have meaning? And ultimately, why do we dream? What the film reveals is that much of what we thought we knew no longer stands true. Dreams are not simply wild imaginings but play a significant part in all our lives as they have an impact on our memories, the ability to learn, and our mental health. Most surprisingly, we find nightmares, too, are beneficial and may even explain the survival of our species.

With optional Hebrew subtitles. This episode explores how the spread of the Enlightenment brought ghetto walls around Europe crashing down and allowed Jews to join the wider fabric of modern life in Europe in unprecedented ways. This Jewish renaissance saw Giacomo Meyerbeer and Felix Mendelssohn to establish the enduring tradition for Jewish musical prodigies. However the integration of Jewish talent into the mainstream of European culture and commerce eventually stirred up ancient prejudice, expressed in the new fashion of Romantic nationalism and the pseudo-science of anti-semitism.

This programme describes the Red Army's dramatic advance and the German's brutal resistance. Witnesses reveal how the final days of the conflict were barbarous almost beyond comprehension.

The film is the inside track on the World's most influential weapon. For over a thousand years this weapon dominated the battlefields of Japan, instilled fear and terror into every enemy it faced, and created a new spiritual way of life that lasts through to the present day. The Samurai sword – a weapon so technologically perfect in structure, so formidable in strength and so beautiful in creation. For the first time unique access has been granted and we travel into the core of the ancient foundries, sword-smiths and fighting schools to reveal what makes the so-called perfect sword. This is a no holds barred look at one of the most iconic man-made objects ever forged.

Mark Oliver Everett, singer of the band EELS, on his quest to get to know his later father, quantum physicist Hugh Everett III, who invented the Many Worlds theory. The film follows Mark on his journey across America, where he meets old friends and colleagues of his father. Hugh died of a heart attack in his home in 1982, where his body was found by 19-year-old Mark. Even though they had lived in the same house, the two of them were alienated. Only by entering the paradoxical world of quantum mechanics can Mark hope to understand why he was such a stranger to his own father.