A protester holds up a sign targeting Salesforce CEO Marc Benioff outside the company's headquarters in San Francisco on Monday. Laura Sydell/NPR hide caption

Eight critically endangered black rhinos died following an attempt to move them from Kenya's capital, Nairobi, to a national park hundreds of kilometers away. Sayyid Abdul Azim/AP hide caption

A homeless man in Denver draws heroin into a syringe. Treatment centers in the city say patterns of drug use seem to be changing. While most users once relied on a single drug — typically painkillers or heroin or cocaine — an increasing number now also use meth. Andy Cross/Denver Post via Getty Images hide caption

Aaron Yoder is training for the world championships for backward running, or retrorunning, in Bologna, Italy. Greg Echlin/KCUR hide caption