An instructor conducts a training session at Transportation Security Administration Academy at the Federal Law Enforcement Training Center, located at a sprawling former air base in Glynco, Ga. Brian Naylor/NPR hide caption

A satellite image of the archaeological site of Tanis, after processing. Sarah Parcak used satellite data to find the ancient Egyptian city. Courtesy of Sarah Parcak hide caption

A Japanese woman in the door of her living quarters in San Bruno, Calif. Dorothea Lange/Courtesy of the Bancroft Library, University of California, Berkeley hide caption

The Keils play with their twins, Matthew and Faith, at their home near Parker, Colo., in 2012. Ed Andrieski/AP hide caption

Democratic presidential candidate Bernie Sanders speaks during a town hall at the University of South Carolina. Sanders promotes the idea of free college education for all. Evan Vucci/AP hide caption