Derrick Johnson, president of the Mississippi NAACP, said at a press conference Wednesday that Donald Trump "clings to the hateful and intolerant rhetoric of this country's shameful history — a history that we know all too well." Sarah McCammon/NPR hide caption

An artist's depiction of the surface of the planet Proxima b as it orbits the red dwarf star Proxima Centauri, the closest star to our solar system. The planet is a bit more massive than Earth, scientists say, and circles its star once every 11 days. ESO/M. Kornmesser/Nature hide caption

Supporters of Sen. Bernie Sanders cheer during a protest near City Hall in Philadelphia during the Democratic National Convention in July. John Minchillo/AP hide caption

A customer tries the Siri voice recognition function on an Apple iPhone 6 Plus in Hong Kong. Bloomberg/Bloomberg via Getty Images hide caption

By testing tumors, researchers hoped to identify women who could avoid chemotherapy without increasing their risk of a cancer recurrence. Voisin/Phanie/Science Source hide caption

As Frankie Reyes, Los Angeles-based musician Gabriel Reyes-Whittaker flips Latin standards into something ghostly and new. Courtesy of the artist hide caption

Tropical Storm Colin brought big waves to Fort Myers Beach in Fort Myers, Fla., in early June. Given the threat of serious flooding, Gov. Rick Scott declared a state of emergency in the area. Joe Raedle/Getty Images hide caption