A migrant from El Salvador holds a map he received from church workers at the Mexico-Guatemala border. It shows the freight train schedules and routes to the U.S. border. Carrie Kahn/NPR hide caption

itoggle caption Carrie Kahn/NPR

Migrants arrive at a rest stop in Ixtepec, Mexico, after a 15-hour ride atop a freight train headed north toward the U.S. border on Aug. 4. Thousands of migrants ride atop the trains, known as La Bestia, or The Beast, during their long and perilous journey through Mexico to the U.S. John Moore/Getty Images hide caption

itoggle caption John Moore/Getty Images

A Mexico City breast-feeding campaigned used posters featuring topless celebrities. At least "La Barbie," a female boxer (shown here), had her boxing gloves on. Via Latin Times hide caption

itoggle caption Via Latin Times

Workers sort through key limes at a packaging house in Apatzingan, Michoacan. More than 90 percent of limes imported into the U.S. come from Mexico. Carrie Kahn/NPR hide caption

itoggle caption Carrie Kahn/NPR

In this June 2013 photo provided by National Geographic, diver Susan Bird, working at the bottom of Hoyo Negro, a large dome-shaped underwater cave in Mexico's Yucatan Peninsula, brushes the Naia skull found at the site. Paul Nicklen/AP hide caption

itoggle caption Paul Nicklen/AP

Joaquin "El Chapo" Guzman is escorted to a helicopter in handcuffs by Mexican navy marines at a navy hanger in Mexico City on Saturday. A senior U.S. law enforcement official said that Guzman, the head of Mexico's Sinaloa Cartel, was captured alive overnight in the beach resort town of Mazatlan. Eduardo Verdugo/AP hide caption

itoggle caption Eduardo Verdugo/AP

The skull of a female Neanderthal, who lived about 50,000 years ago, is displayed at the Natural History Museum in London. Rick Findler/Barcroft Media/Landov hide caption

itoggle caption Rick Findler/Barcroft Media/Landov