In 1943 a squadron of Lancaster bombers staged one of the most audacious raids in military history: destroying two gigantic dams in Germany’s industrial heartland and cutting the water supply to arms factories. Their secret weapon? A revolutionary bouncing bomb invented by British engineer Barnes Wallis. Wallis and the pilots of 617 Squadron—a lively mix of Britons, Australians, Americans, and Canadians—were hailed as heroes who dealt a mighty blow to the German war machine. Now, NOVA recreates the extreme engineering challenges faced by Wallis and the pilots. A crack team of experts, including dam engineers, explosives specialists, mechanics, and aircrew, steps into the shoes of the "dambusters" and attempts to overcome each of the obstacles the original team faced. They must adapt a vintage World War II DC-4 to carry a bomb the size of an oil drum, train to drop it from a dangerously low altitude in pitch darkness, and get it to bounce over obstacles and onto the target, a scale model the German dam struck by the original dambusters. Can they succeed in destroying the dam and unraveling the mysteries of the one-of-a-kind bouncing bomb?

In April, 2010 the eruption of Iceland's Eyjafjallajökull volcano turned much of Europe into an ash-strewn no-fly zone, stranding millions of travelers. But was Eyjafjallajökull just the start? Now, an even more threatening Icelandic volcano, Katla, has begun to swell and grumble. Two more giants, Hekla and Laki, could erupt without warning. Iceland is a ticking time bomb: When it blows, the consequences could be global. As CGI takes us inside these geological monsters, we meet atmospheric scientists who are working to understand just how devastating an eruption could be—not just for air travel but for the global food supply and for Earth's climate.

3,600-year-old reliefs in Egyptian tombs and temples depict pharaohs and warriors proudly riding into battle on horse-drawn chariots. Some historians claim that the chariot launched a technological and strategic revolution, and was the secret weapon behind Egypt's greatest era of conquest known as the New Kingdom. But was the Egyptian chariot really a revolutionary design? How decisive a role did it play in the bloody battles of the ancient world? In "Building Pharaoh's Chariot," a team of archaeologists, engineers, woodworkers, and horse trainers join forces to build and test two highly accurate replicas of Egyptian royal chariots. They discover astonishingly advanced features, including spoked wheels, springs, shock absorbers, anti-roll bars, and even a convex-shaped rear mirror, leading one of them to compare the level of design to the engineering standards of 1930's-era Buicks! By driving our pair of replicas to their limits in the desert outside Cairo, NOVA's experts test the claim that the chariot marks a crucial turning point in ancient military history.