The dome that crowns Florence's great cathedral of Santa Maria del Fiore, the Duomo, is a masterpiece of Renaissance ingenuity and an enduring source of mystery. Still the largest masonry dome on earth, it is taller than the Statue of Liberty and weighs as much as an average cruise ship. Historians and engineers have long debated how its architect, Filippo Brunelleschi, kept the dome perfectly aligned and symmetrical as the sides rose and converged toward the center." More than four million bricks could collapse at any moment -- and we still don't understand how Brunelleschi prevented it. To test the latest theories, a team of U.S. bricklayers will help build an experimental "mini-Duomo" using period tools and techniques.

Stonehenge is an icon of prehistoric British culture, an enigma that has seduced archaeologists and tourists for centuries. Why is it here? What is its significance? And which forces inspired its creators? Now a group of international archaeologists led by the University of Birmingham and the Ludwig Boltzman Institute in Vienna believe that a new state-of-the-art approach is the key to unlocking Stonehenge's secrets. For four years the team have surveyed and mapped every monument, both visible and invisible, across ten square kilometres of the sacred landscape to create the most complete digital picture of Stonehenge and the surrounding area over millennia. Known monuments have yielded more data than ever before, revealing hidden structures within, and new finds are revolutionising the very timeline of Stonehenge. The film takes the viewer on a prehistoric journey from 8000 BC to 2500 BC as the scientists uncover the very origins of Stonehenge, learning why this landscape is sacred, preserved and has been revered by following generations. Evidence of war and conflict, as well as the cultivation of ideas and industry, is explored to reveal complex communities with international trade links as far-reaching as Spain and central Europe.

JFK and the Bay of Pigs; on the brink of total war during Cuban Missile Crisis; early Vietnam; JFK's attempts at peace with Khrushchev; JFK assassinated.

In the second episode of the series, the Germanic tribes strike as Marcus Aurelius succumbs to disease, leaving a skeptical Emperor Commodus to prosecute a war that doesn't interest him.

Are rising temperatures driving Earth's ecosystems past a point of no return? We have promising technologies that put solutions within our grasp. Scientists are exploring solutions: from geoengineering to sucking carbon out of the air to cloud brightening, as means to cool the planet. Cutting-edge solutions and high-risk measures. But would they work? And what are the risks of engineering Earth's climate?

Dawkins opines that the moral framework of religions is warped, and argues against the religious indoctrination of children. He discusses specifically the idea of religion seen as a virus in the sense of a meme. He begins by explaining how a child is genetically programmed to believe without questioning the word of authority figures, especially parents – the evolutionary imperative being that no child would survive by adopting a sceptical attitude towards everything their elders said. But this same imperative, he claims, leaves children open to infection by religion.