Tyson begins the episode by explaining the nature of the speed of light and how much of what is seen of the observable universe is from light emanated from billions of years in the past. Tyson further explains how modern astronomy has used such analyzes via deep time to identify the Big Bang event and the age of the universe. Tyson proceeds to describe how the work of Isaac Newton, William Herschel, and James Clerk Maxwell contributed to understanding the nature of electromagnetic waves and gravitational force, and how this work led towards Albert Einstein's Theory of Relativity, that the speed of light is a fundamental constant of the universe and gravity can be seen as distortion of the fabric of space-time. Tyson describes the concept of dark stars as postulated by John Michell which are not visible but detectable by tracking other stars trapped within their gravity wells, an idea Herschel used to discover binary stars. Tyson then describes the nature of black holes, their enormous gravitational forces that can even capture light, and their discovery via X-ray sources such as Cygnus X-1. Tyson uses the Ship of Imagination to provide a postulate of the warping of spacetime and time dilation as one enters the event horizon of the black hole, and the possibility that these may lead to other points within our universe or others, or even time travel. Tyson ends on noting that Herschel's son, John would be inspired by his father to continue to document the known stars as well as contributions towards photography that play on the same nature of deep time used by astronomers.

With the defeat of the Egyptian fleet at Actium, Mark Antony and Cleopatra retreat to their palace and await their fate. Believing that Cleopatra has taken her life, Mark Antony decides follow her into the afterlife. She has other plans however and is quite prepared to negotiate with Octavian if there is any possibility her life and those of her children will be spared. Cleopatra asks Vorenus to take her son Caesarian to safety and Octavian sends Pullo after them. The old friends are soon together again.

The word Anunnaki means "princely seed" or "princely blood". The idea is that the Anunnaki were direct creations of Anu, who was regarded as the father and king of the gods. Ancient Aliens: "In the ancient texts of Sumeria we have descriptions of these being descending from the sky called the Anunnaki. The term Anunnaki means 'those who from the heavens came."

Foo Fighters prepare to record at the Austin City Limits Studio, with blues guitarist Gary Clark, Jr. In this episode is examined the roots of Austin's music scene, with interviews featuring Billy Gibbons from ZZ Top, and Roky Erickson from 13th Floor Elevators, who is considered one of the American fathers of psychedelic rock. Dave also chats with Terry Lickona, the executive producer of Austin City Limits. The song 'What Did I Do? / God As My Witness' is recorded during this chapter.

In 1971, after being rejected by Hollywood, Bruce Lee returned to his parents' homeland, Hong Kong. Over the next two years, he'd complete four iconic films that would define his legacy, a legacy cut short when he died, stunningly, in the summer of 1973. He was 32 years old. Directed by Bao Nguyen, 'Be Water' is a gripping, fascinating, intimate look at not just those final, defining years of Lee's life, but the complex, often difficult, and seismic journey that led to Lee's ultimate emergence as a singular icon in the histories of film, martial arts, and even the connection between the eastern and western worlds.
The film chronicles Lee's earliest days, as the son of a Chinese opera star born while his father was on tour in San Francisco, and then raised in Hong Kong over what became an at times troubled childhood. Sent to live in America at the age of 18, he began teaching Kung Fu in Seattle, and established a following that included his future wife, Linda. His ambition ever rising, Lee eventually made his way to Los Angeles, where he strove to break into American film and television. There, despite some success as a fight choreographer and actor, it was clear Hollywood wasn't ready for an Asian leading man - and so he returned to Hong Kong to make the films that would in fact make him a legend, his international star skyrocketing just as his life was cut short.
'Be Water' is told by the family, friends, and collaborators who knew Bruce Lee best, with an extraordinary trove of archive film providing an evocative, immersive visual tapestry that captures Lee's charisma, his passion, his philosophy, and the eternal beauty and wonder of his art.

This stylish mix of documentary and historical epic chronicles the reign of Commodus, the emperor whose rule marked the beginning of Rome's fall. In the first episode, the death of Marcus Aurelius brings a century of Roman triumphs and victories to an end, transferring power to his spoiled, unprepared son Commodus. When his father bequeaths him the world's mightiest empire, he is forced to spill the blood of both friends and enemies alike to keep his crown.