# It's a 3-D World! Episode 5 of Physics and Our Universe: How It All Works Series

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Clean
Part of the Series: How We Got to Now
Dirty water has killed more humans than all the wars of history combined, but in the last 150 years, a series of radical ideas, extraordinary innovations and unsung heroes have changed our world. Johnson plunges into a sewer to understand what made a maverick engineer decide to lift the city…
Cold
Part of the Series: How We Got to Now
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Glass
Part of the Series: How We Got to Now
Johnson considers how the invention of the mirror gave rise to the Renaissance, how glass lenses allow us to reveal worlds within worlds and how, deep beneath the ocean, glass is essential to communication. He learns about the daring exploits of glassmakers who were forced to work under threat of…
Light
Part of the Series: How We Got to Now
Johnson relates the story of people who take us out of the dark and into the light. Hear about Edison's light bulb, which he didn't actually invent, and learn how an 18th-century ship's skipper discovered a source of illumination by putting a kid inside a whale's head. See how a…
Sound
Part of the Series: How We Got to Now
Imagine a world without the power to capture or transmit sound. Journey with Johnson to the Arcy sur Cure caves in northern France, where he finds the first traces of the desire to record sound -- 10,000 years ago. He also learns about the difference that radio made in the…