Human Body: Pushing the Limits

Sight is the king of the senses. More than 80 percent of what we know of the world comes through our eyes -- without our sight we're lost. In this episode, we reveal the inner workings of our visual system as they've never been seen before, vividly confirming that ancient human adaptations prove no less crucial in modern life. The astounding hidden powers in our eyes are brought to life by true stories including: * A patrolman relies on the power of sight as he risks his life in a high-speed chase of a murder suspect. * A firefighter crawls through thick smoke in a burning building to seek survivors using innate night vision and clues decoded by his brain's vision center. * A lifeguard applies his remarkable skills of pattern recognition to spot one drowning man amid thousands at the beach. Plus, how do magicians fool us with their illusions? What lies behind the mysteries of our dreams? And what new powers will be discovered by the latest scientific breakthroughs enabling doctors to plug a camera directly into the brain?

The human body is engineered for strength, power and endurance. Bone is sturdy as concrete but flexible enough to resist breaking and light enough to allow us to be quicker off the mark than a racehorse. Our muscles, ligaments and joints have far greater strength and endurance than we know. In this episode, we feature extraordinary tales of human strength told with stunning see-through "anatomy in motion." * A young man is sucked up into a tornado, only to be spat out a quarter of a mile away, unharmed. * Pinned by a massive boulder, a climber finds the strength to lift it off in a seemingly impossible muscular feat. * A college football player sustains what would normally be unbearable injury and pain, yet has the mental stamina to continue playing at full output. Plus, how does a swimmer tap the remnants of our distant ancestors' extraordinary stamina to swim across the English Channel in 14 hours? How do marathon runners keep the pace on their grueling 26-mile run?

Less than one-twentieth of an inch below the surface of the skin are the "antennae" that allow us to sense the world around us. This vital layer is the gateway to the original information superhighway -- the nervous system. Millions of nerves carry sensations across the body and up to the brain at hundreds of miles an hour. But our nervous system also has abilities almost beyond imagining. Here is the story of the human body's crucial communications network as never seen before: * When a father and daughter are stranded without water in the scorched Australian outback, a countdown to their death begins until their nerves trigger hidden survival systems. * Rapid response wiring in his body allows a Coast Guard helicopter pilot to control his machine with amazing precision, even in storm-strength winds. * A life of intense training and mental discipline allows Shaolin monks to endure powerful blows to their bodies without even blinking. Plus, how can we move our fingers faster than we can think? How can you master the polygraph? What exactly is pain, and how do some control it?

The driving force behind every one of us is the most powerful organ in the natural world: the human brain. Our central processing unit generates as many electrical impulses in a single day as all the telephones in the world combined. With new state-of-the-art imagery of this complex, mysterious machine, we reveal how our brain accelerates when faced with intense stress or danger, and taps into its deepest layers to unlock prehistoric survival instincts. * NASCAR driver Clint Bowyer tells us about making split-second decisions in the heat and stress of a 400-lap race. * Desperate firefighters, trapped by the intense heat of a forest fire, find out how the brain can take charge without waiting for conscious control. * A lone explorer, piloting a balloon over the Arctic, pushes himself to the limits of sleep deprivation. It nearly costs him his life. Plus, learn about the extraordinary ways our brains can re-tune our system when starvation threatens, and how sleep and dreams can unleash unseen powers in our mind.