Brian Cox looks at our attempts to answer one of the most profound questions we can ask – are we alone in the universe? With scientists sending space probes to the furthest reaches of our solar system and beyond, the scientific search for alien life has begun. Inspired by a childhood love of science fiction, Brian still hopes to hear from ET. In this film, he explains why this search deserves to be taken seriously, and he explores the chances of it happening.

Right now cosmic forces prowl the universe and threaten man's very existence. They're asteroids and comets; they've left their imprint on planet Earth, literally. Initially helping to build planets through violent collisions, during this fiery bombardment period they may have even seeded Earth with water and the building blocks for life. Since the turbulent formation of the solar system, these space rocks have continued to impact Earth. Some have been so violent that they've led to mass extinctions, including one that wiped out the dinosaur. New theories suggest that asteroid and comet dust harbour deadly viruses that may have triggered some of our worst pandemics. The possibility of future collisions remains a legitimate threat yet despite their dangers, asteroids and comets may hold vital natural resources, which could actually preserve

Washington, D.C. is in many ways a city of extremes. Starland Vocal Band, Marvin Gaye, Duke Ellington, Nils Lofgren, Chuck Brown, Henry Rollins, Fugazi and Trouble Funk all hail from D.C. In the early '70s, the music style go-go originated here, and has remained a local craze ever since. Dave Grohl sits down with Trouble Funk's Big Tony Fisher to talk about go-go, and explores its origins with Chuck Brown, the genre's undisputed godfather.
He also chats with Don Zientara, owner of Inner Ear Studios, which the Virginia-raised Grohl says 'produced the entire soundtrack of my youth,' as well as with members of the harDCore band Bad Brains and Ian MacKaye of Teen Idles, Minor Threat and Fugazi, who all recorded at Inner Ear over the decades. The song 'The Feast and the Famine' is recorded during this episode.

Follow the dramatic personal journey of Hugh Herr, a biophysicist working to create brain-controlled robotic limbs. At age 17, Herr’s legs were amputated after a climbing accident. Frustrated by the crude prosthetic limbs he was given, Herr set out to remedy their design, leading him to a career as an inventor of innovative prosthetic devices.
Now, Herr is teaming up with an injured climber and a surgeon at a leading Boston hospital to test a new approach to surgical amputation that allows prosthetic limbs to move and feel like the real thing. Herr’s journey is a powerful tale of innovation and the inspiring story of a personal tragedy transformed into a life-long quest to help others.

Three years after the devastating fire, Lucy Worsley has exclusive access to the Cathedral of Notre-Dame de Paris at a key turning point of the restoration. Work to rebuild and restore the monument is being ramped up in a bid to meet the ambitious deadline to reopen it to the public in 2024. Scaffolding now fills the interior of the cathedral, giving Lucy and the team unprecedented close-up access to every inch of the structure. Lucy meets scientists, historians and craftspeople working to return the 850-year-old Gothic masterpiece to its former glory.
The fire coated Notre-Dame with tons of toxic lead dust, so specialists are now decontaminating the site. Unique access to the stunning rose windows allows Lucy and the stained-glass historians to uncover the mysteries of these enigmatic 13th-century works of art. An unforeseen legacy of the fire threatens to destroy the remaining vaulting, so the team must develop an ingenious solution to save the stonework. The loss of the roof during the fire reveals hundreds of large iron staples embedded in the stone along the top of the walls. And the incredible task of sourcing and cutting two-thousand perfect oaks gets underway to rebuild the world's most complex medieval timber structure - Notre-Dame's extraordinary roof and spire.

This episode discusses the human exploration of Antarctica, in particular the mission led by Captain Robert Falcon Scott, whose team died on the way back from the South Pole. It shows the scientific work in the modern human bases in Antarctica, especially Mawson Base and its observation of Adelie Penguins (partially through tracking devices). The second half of the episode describes how the series was made. Most crucial was of course the camera work. To get access to the wildlife of the sea, for example, boats, divers, suspended capsules and remotely controlled cameras mounted on inflatables were used. Particularly dangerous to divers were Leopard Seals and other predators. The film concludes that although working in Antarctica is now much easier than during the early days of exploration, human footsteps on the continent are still exceedingly rare in part because of international treaties prohibiting industrial exploitation.