Decades ago, the border fence near the port of entry at Nogales, Ariz., and Nogales, Mexico, was made of wire mesh. Now it's a thick steel wall covered with graffiti. Loosely translated, this part of the wall says "Walls Equal Death," although the end of the phrase is not shown. Claudio Sanchez/NPR hide caption

itoggle caption Claudio Sanchez/NPR

As winter approaches, Bill Thompson gave Melissa Block's backyard in Washington, D.C., a bird feeding makeover. "It's the time of year most folks start feeding actively, cause we get a lot of the northern birds coming down for the winter, to what they feel is our milder climate," he says. Here, an Eastern bluebird sits on an icy feeder. Bill Thompson III hide caption

itoggle caption Bill Thompson III

The deep-water-research submarine Alvin is launched from Atlantis. Scientists are studying how ecosystems in the Gulf of Mexico may have been affected by the Deepwater Horizon oil spill. Richard Harris/NPR hide caption

itoggle caption Richard Harris/NPR

Russian councilman Jean Gregoire Sagbo speaks in the administration office in Novozavidovo, a village 60 miles north of Moscow, on July 20. As the first black man elected to public office in Russian history, he has been nicknamed Russia’s Obama, something he’s not too pleased about. Sergey Ponomarev/AP hide caption

itoggle caption Sergey Ponomarev/AP

Katherine Hamilton during a 1981 hurdles race when she was a sophomore at Berkeley. Later that year, Hamilton quit the team and walked away from her sport, largely because of the prevalence of performance-enhancing drugs at the top levels of track and field. Courtesy of Martha Edwards hide caption

itoggle caption Courtesy of Martha Edwards

MIT researchers wore the Age Gain Now Empathy System -- a body suit and helmet -- to a grocery store to understand what struggles seniors might have while shopping. Courtesy of MIT's AgeLab hide caption

itoggle caption Courtesy of MIT's AgeLab

This 1905 steam engine powered factories in Holland, Mich., for more than half a century (with a four-year break during the Great Depression). It now sits as a monument to the city's industrial heritage. Scott Horsley/NPR hide caption

itoggle caption Scott Horsley/NPR

An ethnic Uzbek mother and son wait at the Kyrgyz-Uzbek border outside the village of Suratash, Kyrgyzstan, on June 14. Uzbek and Kyrgyz alike are trying to make sense of ethnic violence that took place last month. Oxana Onipko/AFP/Getty Images hide caption

itoggle caption Oxana Onipko/AFP/Getty Images