This episode explores the wave theory of light as studied by mankind, noting that light has played an important role in scientific progress, with such early experiments from over 2000 years ago involving the camera obscura by the Chinese philosopher Mozi. Tyson describes the work of the 11th century Arabic scientist Ibn al-Haytham, considered to be one of the first to postulate on the nature of light and optics leading to the concept of the telescope, as well as one of the first researchers to use the scientific method. Tyson proceeds to discuss the nature of light as discovered by mankind. Work by Isaac Newton using diffraction through prisms demonstrated that light was composed of the visible spectrum, while findings of William Herschel in the 19th century showed that light also consisted of infrared rays. Joseph von Fraunhofer would later come to discover that by magnifying the spectrum of visible light, gaps in the spectrum would be observed. These Fraunhofer lines would later be determined to be caused by the absorption of light by electrons in moving between atomic orbitals when it passed through atoms, with each atom having a characteristic signature due to the quantum nature of these orbitals. This since has led to the core of astronomical spectroscopy, allowing astronomers to make observations about the composition of stars, planets, and other stellar features through the spectral lines, as well as observing the motion and expansion of the universe, and the existence of dark matter.

The 1980s was an era in which a fusillade of new genres emerged, and many are still with us today, such as hip-hop and house. Dylan Jones has mined the archives to select some of the most crucial tracks in the rise of these two genres.
From a young Kurtis Blow making his Top of the Pops debut to the sonic bombardment of Public Enemy and the sampling skills of Bomb the Bass, this episode showcases the evolution in rap and house music across the decade. There are rare archival interviews and stellar performances from Run-DMC, Salt 'N' Pepa, S'Express, Cookie Crew and Neneh Cherry, as well as iconic videos from Herbie Hancock, The Beastie Boys, M/A/R/R/S, Grandmaster Flash and the Furious Five, and many more.

The final hours of WW2 changed the course of history. As the Americans inch closer to Japan the Japanese fight with greater intensity. The question now is how to end the conflict. Starve them into capitulation? Many in US command believe the Japanese will never surrender. The alternative is to stage a massive invasion that would dwarf D-Day? The massacre of millions would be inevitable. But then a third and far darker option becomes available: the atom bomb.

It was the defining moment of the 20th Century - the scientific, technological, military, and political gamble of the world's first atomic attack. This drama-documentary attempts to do what no other film has done before - to show what it is like to live through a nuclear explosion, millisecond by millisecond. Set in the three weeks from the first test explosion in New Mexico to the eventual dropping of the bomb, the action takes viewers into the room where the crucial political decisions are made; on board the Enola Gay on her fateful voyage; inside the bomb as it explodes; and on the streets of Hiroshima when disaster strikes. Parallel storylines interweave, unfolding the action from both US and Japanese perspectives, and revealing the tensions and conflicts in the actions and minds of people who were making history. Special effects recreate the reality of the mission - even going inside the workings of the bomb - and archive film replays the horrific aftermath.

It was the defining moment of the 20th Century - the scientific, technological, military, and political gamble of the world's first atomic attack. This drama-documentary attempts to do what no other film has done before - to show what it is like to live through a nuclear explosion, millisecond by millisecond. Set in the three weeks from the first test explosion in New Mexico to the eventual dropping of the bomb, the action takes viewers into the room where the crucial political decisions are made; on board the Enola Gay on her fateful voyage; inside the bomb as it explodes; and on the streets of Hiroshima when disaster strikes. Parallel storylines interweave, unfolding the action from both US and Japanese perspectives, and revealing the tensions and conflicts in the actions and minds of people who were making history. Special effects recreate the reality of the mission - even going inside the workings of the bomb - and archive film replays the horrific aftermath.

Richard Rudgley goes in search of evidence of the barbarians of the dark ages, people whose names have for 1500 years been bywords for mindless brutality. The real truth about the barbarians who marched across Europe during the Dark Ages is more shocking than what you may know. Where did they come from? Who are their descendants? Are any of their techniques and inventions still used? Richard discovers the secrets of forgotten empires, and of mighty clashes throughout Europe. The art, society and cultural legacy of the barbarians are shown to have shaped and moulded the destiny of Europe even more than the Roman Empire.
In the first part of the journey through the Dark Ages we will be tracing the legacies of the Huns, Vandals and Goths, to ask whether the 'dark ages' represent a resurfacing of much older tribal lines. Sites in Austria show how sophisticated pre-Roman communities had become with evidence of stunning craftsmanship and sophisticated farming techniques which defy the image of a mindless rabble we have come to accept without challenge.