In 1901, a group of divers excavating an ancient Roman shipwreck near the island of Antikythera, off the southern coast of Greece, found a mysterious object - a lump of calcified stone that contained within it several gearwheels welded together after years under the sea. The 2,000-year-old object, no bigger than a modern laptop, is now regarded as the world's oldest computer, devised to predict solar eclipses and, according to recent findings, calculate the timing of the ancient Olympics. Following the efforts of an international team of scientists, the mysteries of the Antikythera Mechanism are uncovered, revealing surprising and awe-inspiring details of the object that continues to mystify

The Internet promises us escape from reality. We can go places we never thought possible and express ourselves as never before. But as we sit in our homes surrounded by screens, are we free... and safe? In this episode meet a woman pulled into an online cult from the safety of her bedroom; a former pilot who suffers from Electromagnetic Hypersensitivity and can only find relief in the absence of electricity and wifi; plus, a quadriplegic who uses cutting-edge adaptive robotics and virtual reality to transcend his body's limitations.

One of Britain's most celebrated artists, Turner showed exceptional artistic talent from an early age and entered the Royal Academy aged fourteen. His English landscapes made his name but there was a darker side to his paintings that was difficult for the critics to swallow, both in the increasingly informal use of paint and the subject matter that was critical of the romanticised vision of Britain in the late nineteenth century.

Tyson describes the discovery of cosmic rays by Victor Hess through high-altitude balloon trips. Swiss Astronomer Fritz Zwicky, in studying supernovae, postulated that these cosmic rays originated from these events instead of electromagnetic radiation. Also tells how Vera Rubin observed that the rotation of stars at the edges of observable galaxies did not follow expected rotational behavior leading to consider the existence of dark matter. This further led to the discovery of dark energy to account for the increasing rate of expansion of the universe. Tyson then describes the interstellar travel of the two Voyager probes. Tyson tells the Carl Sagan's role in the Voyager program, including creating the Voyager Golden Record to encapsulate humanity and Earth's position in the universe. Tyson concludes the series by emphasizing Sagan's message on the human condition in the vastness of the cosmos, and to encourage viewers to continue to explore and discover what else the universe has to offer.

In episode two, we discover the golden age of the La Tene Celtic warrior and reveal how their world extended as far as central Turkey. But by the middle of the first century BC, the Celts were under threat from an expanding Roman Empire, and the Gallic warrior Vercingetorix would challenge Julius Caesar in an epic battle that would shape the future of Europe.

In 1914, Russia entered World War I in response to Austria-Hungary's declaration of war on Russia's ally Serbia. This was fought across multiple fronts while isolated from its allies. The Battle of Tannenberg, where the entire Russian Second Army was annihilated, cast an ominous shadow over the empire's future. The already-existing public distrust of the regime was deepened by the rising costs of the war and rumours of corruption. World War I takes Nicholas to the front. Back home, outrage grows over high casualties and Alexandra and Rasputin's political intrigues.