Nialina Ba holds the only picture she has of her late husband, Bourang Ba (in the white shirt). Ofeibea Quist-Arcton/NPR hide caption

Democratic presidential candidate Bernie Sanders addresses the crowd Tuesday during a campaign rally at the Big Four Lawn park in Louisville, Ky. John Sommers II/Getty Images hide caption

Former professional boxer, Iran Barkley, poses in front of his Bronx apartment complex. Barkley, a former WBC middleweight champion, became homeless after facing financial troubles in the later years of his life. He currently is a board member of Ring 10 Veterans Boxing Foundation of New York, an organization that works with boxers who are down on their luck. Cameron Robert/NPR hide caption

A kindergarten teacher in Jerusalem stands with students as they listen to sirens that played nationwide on Thursday to commemorate Holocaust Remembrance Day. This year, a new national Holocaust curriculum is being fully implemented in kindergarten. Ellen Krosney for NPR hide caption

Sen. Ben Sasse hands out water at the Lincoln Marathon in Nebraska. The Republican has vowed not to vote for Trump and is calling for a third candidate to emerge. Sarah McCammon/NPR hide caption

A sugar beet. This crop supplies about half of America's sugar. iStockphoto hide caption