Transgender performers walk backstage during an event to mark World AIDS Day in 2013. A new WHO report demonstrates extremely rates of HIV infection among transgender women in 15 countries. Prakash Mathema/AFP/Getty Images hide caption

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A baby helps make history. The Kenyan child is receiving the new malaria vaccine — the first ever that can wipe out a parasite — as part of a clinical trial. Karel Prinsloo/AP hide caption

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Teacher Kim Song Bo lectures at a new school that is training students to make prosthetic limbs. Classes are held at the Center for the Rehabilitation of the Paralyzed in Dhaka, Bangladesh. Amy Yee/NPR hide caption

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British actress Zawe Ashton and Agnes Pareyio, who underwent female genital mutilation as a girl in Kenya, are two of the activists featured in "Stop Cutting Our Girls," a documentary opposing the practice. Pontso Mafethe/Courtesy of Pontso Mafethe hide caption

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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

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Slum dwellers near Calcutta get their water from a municipal pipe. Water coming out of the tap on the left is for bathing and so is untreated. The blue Zimba chlorinator is hooked up to the tap on the right, which is used for drinking water. Courtesy of Suprio Das/Zimba hide caption

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"What has happened in the last ten years, has been a remarkable increase in actual number of people who are dying or are not able to get better because they carry a resistant infection."--Ramanan Laxminarayan Courtesy of TEDMED hide caption

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Ioanna Mattke holds Raven, one of six hens that her family owns. The Mattkes have raised Raven since she was a day old. Jason Beaubien/NPR hide caption

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The Cryptsporidium parasite emerges from the oocyst ready to infect. Muthgapatti Kandasamy & Boris Striepen/Courtesy of University of Georgia hide caption

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Activists in Sri Lanka got an early start on the day of action, with a demonstration by 800 people in Negombo province on the Sri Lanka's western coast. Courtesy of action/2015 hide caption

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A family receives treatment for cholera at a clinic run by Doctors Without Borders in Port-au-Prince, Haiti, in October 2011, a year after the overwhelming outbreak began. Ramon Espinosa/AP hide caption

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Street children sleep on a discarded mattress on a center island near a road crossing in Manila, Philippines, in April. After 15 years of the Millennium Development Goals, Asia as a region has had the fastest progress, reports the U.N., yet hundreds of millions of people there remain in extreme poverty. Jay Directo/AFP/Getty Images hide caption

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Health workers wash their hands after taking a blood sample from a child to test for the Ebola virus. On Tuesday, the workers tested people in the village outside Monrovia where a 17-year-old boy died of the disease over the weekend. Abbas Dulleh /AP hide caption

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