Workers stand next to a gas pipeline not far from the central Ukrainian city of Poltava in June 2014. Ukraine imports much of its gas from Russia, which is once again threatening to cut off supplies in a dispute over payments. Sergei Supinsky/AFP/Getty Images hide caption

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Lincoln has invested hundreds of millions of dollars in revitalizing its downtown, a historic area called Haymarket, to create a more culturally vibrant urban center that is helping the city keep and attract young adults. David Schaper/NPR hide caption

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In exchange for a fee of 60 euros, members of Adopt A Cow get an assortment of aged and soft cheeses made from the milk of cows like Mery. Christopher Livesay for NPR hide caption

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Jorge Cham is the creator of PHD Comics and received his doctorate in mechanical engineering at Stanford University. PHD (Piled Higher and Deeper) is a comic strip about life (or the lack thereof) in academia. See more of his work at www.phdcomics.com. Jorge Cham/PHD Comics hide caption

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President Obama remarks on his proposal to tighten consumer protections for people saving for retirement as Sen. Elizabeth Warren and Labor Secretary Tom Perez listen, at AARP on Monday. Getty Images hide caption

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