3-D renderings of four skeletons found buried near the altar of an early church in the Jamestown settlement in Virginia. Smithsonian X 3D hide caption

itoggle caption Smithsonian X 3D

A Yale University study analyzed the experience of 60 million Americans covered by traditional Medicare between 1999 and 2013, and found "jaw-dropping improvements in almost every area," the lead author says. Ann Cutting/Getty Images hide caption

itoggle caption Ann Cutting/Getty Images

A nanosecond pulsed laser beam starts the photoacoustic imaging process. Geoff Story/Courtesy of Washington University in St. Louis hide caption

itoggle caption Geoff Story/Courtesy of Washington University in St. Louis

A daily habit of sugary-sweetened drinks can boost your risk of developing the disease — even if you're not overweight. Ryan Kellman/NPR hide caption

itoggle caption Ryan Kellman/NPR

Giedre (left) and Tal Cohen in March 2013, while Giedre was still healthy. Since then, she's begun having symptoms of Alzheimer's disease. In Giedre's case, the illness is tied to a rare genetic mutation she inherited. Courtesy of Tal Cohen hide caption

itoggle caption Courtesy of Tal Cohen

Women with mild cognitive impairment, which can be a precursor to Alzheimer's, tend to decline faster than men. Lizzie Roberts/Getty Images/Ikon Images hide caption

itoggle caption Lizzie Roberts/Getty Images/Ikon Images

The area around the confluence of the Silverthrone and Klinaklini glaciers in southwestern British Columbia provides a glimpse into how the terrain traveled by Native Americans in Pleistocene times may have appeared. David J. Meltzer/Science hide caption

itoggle caption David J. Meltzer/Science

Lee Perry-Gal measures chicken long bones at the zooarchaeology lab, Zinman Institute of Archaeology, University of Haifa. Courtesy of Guy Bar-Oz hide caption

itoggle caption Courtesy of Guy Bar-Oz

In this colorized image of a brain cell from a person with Alzheimer's, the red tangle in the yellow cell body is a toxic tangle of misfolded "tau" proteins, adjacent to the cell's green nucleus. Thomas Deerinck/NCMIR/Science Source hide caption

itoggle caption Thomas Deerinck/NCMIR/Science Source

Floodwaters from rising sea levels have submerged and killed trees in Bedono village in Demak, Central Java, Indonesia. As oceans warm, they expand and erode the shore. Residents of Java's coastal villages have been hit hard by rising sea levels in recent years. Ulet Ifansasti/Getty Images hide caption

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Lorenzo Gritti for NPR