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.

As tides rise and fall twice a day, vast amounts of water swirl around the earth. This is a huge energy source that's currently largely untapped. An estimated 3000 gigawatts are available to be harvested globally, enough to power a third of the earth's homes. Yet compared to wind and solar, the technology needed to harness tidal power is still in its infancy. The power of the ocean’s tides is the last great untapped energy source on Earth. From sub-sea kites to floating platforms, teams of engineers are racing to perfect the technology to harness the vast flows of water.

Located in Central America, Tikal is one of the largest of the ancient cities of the Mayan civilization. Occupied for more than a millennium, Tikal, founded in the 8th century BC and nestled in the jungle of Guatemala, will have up to 12,000 structures and reach over 2 million inhabitants.
This episode shows its extraordinary pyramid-temples, designed with human power alone. Thanks to new technologies, the ancient Mayan city is revealed there, entirely reconstituted in 3D synthetic images.

In an adventure of giant proportions, The film reveals the astonishing lives of the smallest of animals. Using the incredibly immersive power of specialist 3D cameras, audiences will be transported in a very intimate way into another world and experience the titanic battles these creatures face to survive.

Titanic 100 Years combines stunning imagery of the wreck with powerful untold stories of passengers and crew, letting audiences experience the real life drama of Titanic in a way never before possible. In 2010, an unprecedented expedition by Woods Hole Oceanographic Institute and RMS Titanic, Inc. went on location to document the entire wreck site of Titanic, using high-resolution optical video, sonar, acoustic imaging, and 3D HD video and acoustic modeling.
These incredible visuals are accompanied by the untold stories of people who were on the ship and linked with one or more recovered artifacts that connect to that passenger or crewmember. These haunting artifacts and unforgettable personal stories of average people take viewers back in time, making the history of Titanic as vivid as it was yesterday.

Every day of our lives, we are bombarded by thousands of different images, images which affect us in countless different ways. But of all these there's one particular kind of image whose power is uniquely mesmerising, because while it terrifies us somehow it also comforts. But although it can manipulate us, it also reassures, It's the image of death.