Hundreds of thousands of people crowd Copacabana Beach in Rio de Janeiro on Sunday as Pope Francis celebrates the final Mass of his visit to Brazil. Security lapses, traffic chaos and other logistical snafus marred the visit. AFP/Getty Images hide caption

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Mild-mannered teacher by day, masked superhero by night, the Burka Avenger fights corruption and oppression, and aims to empower the girls of Pakistan. Unicorn Black Studios hide caption

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The bite of a cobra can paralyze its victims and, if enough venom is released, fatally stop their breathing. It's estimated that more than 75 percent of patients in India who die from a snake's bite never make it to the hospital. STRDEL/AFP/Getty Images hide caption

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Saudi women get into a taxi outside a shopping mall in Riyadh in 2012. Plans for a subway system in the Saudi capital are likely to provide the biggest benefits to women and the poor. Fayez Nureldine/AFP/Getty Images hide caption

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Ali Maow Maalin said he avoided getting the smallpox vaccine as a young man because he was afraid of needles. He didn't want others to make the same mistake with polio. Courtesy of the World Health Organization hide caption

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Anti-gay protesters try to attack a bus with gay activists who are being taken away from a pro-gay-rights rally by police for their own protection in Tblisi, Georgia, on May 17. Thousands of anti-gay protesters, including Orthodox priests, occupied a central street in Georgia's capital. Shakh Aivazov/AP hide caption

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New York-based composer Mohammed Fairouz. Samantha West/Courtesy of the artist hide caption

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Flowers pay tribute to the victims of the train that crashed in northwestern Spain last week. The driver of the train was on the phone and traveling at nearly twice the speed limit, according to court papers. Rafa Rivas/AFP/Getty Images hide caption

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Secretary of State John Kerry leaves the West Wing of the White House with chief negotiators, Israeli Justice Minister Tzipi Livni (back to camera), Palestinian negotiator Saeb Erekat (right) and others, after a meeting with President Obama on Tuesday. Brendan Smialowski /AFP/Getty Images hide caption

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