This episode explores the nature of the greenhouse effect (discovered by Joseph Fourier and Svante Arrhenius), and the evidence demonstrating the existence of global warming from humanity's influence. Tyson begins by describing the long-term history of the planet Venus; based on readings from the Venera series of probes to the planet, the planet had once had an ocean and an atmosphere, but due to the release of carbon dioxide from volcanic eruptions, the runaway greenhouse effect on Venus caused the surface temperatures to increase and boiled away the oceans. Tyson then notes the delicate nature of the amount of carbon dioxide in the atmosphere can influence Earth's climate due to the greenhouse effect, and that levels of carbon dioxide have been increasing since the start of the 20th century. Evidence has shown this to be from mankind's consumption of oil, coal, and gas instead of from volcanic eruptions due to the isotopic signature of the carbon dioxide. The increase in carbon dioxide has led to an increase in temperatures, in turn leading to positive feedback loops of the melting polar ice caps and dethawing of the permafrost to increase carbon dioxide levels. Tyson then notes that humans have discovered means of harvesting solar power, such as Augustin Mouchot's solar-driven motor in the 19th century, and Frank Shuman's solar-based steam generator in the 1910's. Tyson points out that in both cases, the economics and ease of using cheap coal and oil caused these inventions to be overlooked at the time. Today, solar and wind-power systems would be able to collect enough solar energy from the sun easily. Tyson then compares the motivation for switching to these cleaner forms of energy to the efforts of the Space race and emphasizes that it is not too late for humanity to correct its course.

Chinese 'Cockblock'. In China, where marrying-age men outnumber women by the millions, discover the lucrative business catered to matchmaking and the bachelors who use such services. 'European Meltdown' With their economy in the toilet and no jobs to be had, Europe's youth are taking to the streets to demand radical changes.

Oil theft has become big business in Nigeria. Travel to this Africa's oil-producing region to meet with oil thieves, and follows one farmer's attempt to sue a foreign oil company for poisoning his family's land. The lethal combination of gangs and guns has turned Chicago into a war zone. Visit the city's most dangerous areas.

Someone once observed: 'America is great because she is good; if she ever ceases to be good she will cease to be great.' Today that notion of the essential goodness of America is under attack, replaced by another story in which theft and plunder are seen as the defining features of American history-from the theft of Native American and Mexican lands and the exploitation of African labor to a contemporary foreign policy said to be based on stealing oil and a capitalist system that robs people of their "fair share"

Journey through the long-vanished corners of prehistoric North America, beginning when man first entered the vast, unspoiled continent some 14,000 years ago, in this appealing BBC documentary. Witness ancient beasts, mammoths, mastodons, giant bears, and sabre-toothed cats, and see the legacies each has passed to their modern successors. Computer animation and digital effects bring to life mammoths, saber-toothed cats, giant ground sloths, short-faced bears, glyptodonts, and a plethora of smaller animals in a lush Ice Age mosaic. Discoveries from sites across America are the basis for the reconstructions.

Are the rings of Saturn a real celestial phenomenon or merely a cosmic Illusion? Technology allows the experts to get closer to the furthest planet visible to the naked eye. Old questions are answered and new ones arise. Does Saturn hold the key to Earth's weather and will one of its moons supply us with all the oil we'll ever need?