For the first time, scientists have synthesized a three-stranded molecular braid that twisted into a knot with eight crossings, as in this rendering. Stuart Jantzen/Biocinematics.com/Science hide caption

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Stuart Jantzen/Biocinematics.com/Science

Scientists Have Twisted Molecules Into The Tightest Knot Ever

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Volkswagen has agreed to plead guilty to three criminal felony counts as part of the settlement announced Wednesday by the Justice Department. Damian Dovarganes/AP hide caption

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Damian Dovarganes/AP

In March 2015, Steven McDonald gathered with his wife, Patricia, and son, Conor, to receive the Spirit of Giving Award at the Kelly Cares Foundation's 5th Annual Irish Eyes Gala, in New York City. Stuart Ramson/Invision for Kelly Cares Foundat hide caption

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Stuart Ramson/Invision for Kelly Cares Foundat

A deer was stuck to ice for over three hours in Simsbury, Conn., on Monday. It was rescued by wildlife officials and the event was streamed via Facebook Live. NBC4 Columbus/Screenshot by NPR hide caption

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NBC4 Columbus/Screenshot by NPR

This undated photo appeared on a website investigated by the FBI in connection with Dylann Roof, who killed nine people in a Charleston, S.C., church in June 2015. AP hide caption

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AP

Dylann Roof FBI Interview Excerpt

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Veteran British war correspondent Clare Hollingworth, who broke the story that the World War II had begun, celebrates her 100 birthday during a party at the Foreign Correspondents' Club in Hong Kong in 2011. She celebrated her 105th birthday there this past October. Laurent Fievet/AFP/Getty Images hide caption

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In 1972, NPR invited listeners to write ads for stuff money can't buy. We're doing it again this year. But first, to jog your thinking, here are a few examples of the more, well, unique ads back then, including one sung by a toddler about firetrucks. Chelsea Beck/NPR hide caption

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Chelsea Beck/NPR

Big Nothings

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Debbie Reynolds and her daughter, Carrie Fisher, at the Primetime Creative Arts Emmy Awards in 2011 in Los Angeles. Reynolds' death, just one day after her daughter's, has led many to ask whether it's really possible to die of a broken heart. Chris Pizzello/AP hide caption

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Astronomers searching for an undiscovered planet in the outer solar system hope to catch a glimpse of it Thursday through the Subaru Telescope located on top of Hawaii's Mauna Kea mountain. Courtesy of the National Astronomical Observatory of Japan hide caption

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Courtesy of the National Astronomical Observatory of Japan

Astronomers Seeking Planet 9 Hope To Soon Catch A Glimpse

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George Michael performs a charity concert for Sidaction, an AIDS nonprofit, at the Palais Garnier opera house in Paris in 2012. Eddy LeMaistre/Corbis via Getty Images hide caption

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Eddy LeMaistre/Corbis via Getty Images
Chelsea Beck/NPR

Cumulus Clouds

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