Experts agree that the image on the left urges toilet users to flush toilet paper in the bowl rather than toss it in a trash can. As for the image on the right, it appears to offer a double warning: Don't stand on the seat, don't relieve yourself in the upper tank. Jennifer Wood/Courtesy of Doug Lansky hide caption

Francescangeli says boys sometimes work long hours and are often tasked with pushing carts to move rocks out of the mines. "Being a child in these places is really hard," he says. "If they have some time to spend in a free way, they like to be children. But their life doesn't permit them to be children so often." Simone Francescangeli hide caption

A tsetse fly photographed in the zoological institute of the Slovak Academy of Sciences in Bratislava. Tsetse fly bites transmit the parasitic disease called sleeping sickness. Anton Fric/AP hide caption

Health workers help an unconfirmed Ebola patient into her bed inside a treatment center in Democratic Republic of the Congo. John Wessels/AFP/Getty Images hide caption

Sara, a 10-year-old at al Thawra hospital in Hodeidah, Yemen, is half paralyzed by diphtheria, an illness that can be prevented by vaccination. She subsequently had to leave the hospital because of the violence. UNICEF/Touma/Yemen/2018 hide caption

The circles on the map pinpoint the location of thousands of Chinese-funded development projects. The bigger the circle, the bigger the investment. The largest circles represent projects in the multibillion-dollar range. Map by Soren Patterson, AidData/William & Mary/Screenshot by NPR hide caption

Hanna Barczyk for NPR Hanna Barczyk for NPR hide caption

How the U.S. Compares with the Lowest Rates of Violent Gun Deaths Worldwide NPR hide caption

Bill Gates, co-founder of the Bill & Melinda Gates Foundation, gestures to a jar of human feces as he speaks at the Reinvented Toilet Expo in Beijing on November 6. Mark Schiefelbein/AP hide caption

Sister Bertha Lopez Chaves applies anti-inflammatory eyedrops to a migrant at a stadium in Mexico City where the caravan is resting. Her order is one of roughly 50 groups giving aid to the migrants in the Mexican capital. "We're just trying to deal with their basic needs so they can continue on," she says. James Fredrick for NPR hide caption

Jacob Atem, who fled Sudan as a boy, was one of the storytellers at "Stoop Stories," a Baltimore event. Atem talked about his life as a "Lost Boy" and what happened when he settled in Michigan — like the time his foster mom grounded him just for wanting to punch a kid who'd insulted him. Brennen Jensen for NPR hide caption

A migrant who scaled a border fence from Morocco into the Spanish enclave of Melilla shows their injured hands, in March 2014. Spain is seeing a record of largely sub-Saharan African migrants and asylum-seekers making risky journeys to enter the country. AFP/Getty Images hide caption

Freya, a springer spaniel, is in training to detect malaria parasites in sock samples taken from children in Gambia. Two canine cohorts were used in a study on malaria detection. Durham University/Medical Detection Dogs/London School of Hygiene & Tropical Medicine hide caption

A Yemeni child suffering from malnutrition lies on a bed at a treatment center in a hospital in the capital, Sanaa. Mohammed Huwais/Getty Images hide caption

A nurse vaccinates a baby against rotavirus, a deadly form of diarrhea. Hector Retamal/AFP/Getty Images hide caption

Engraving from a series of images titled "The Great Yellow Fever Scourge — Incidents Of Its Horrors In The Most Fatal District Of The Southern States." Bettmann Archive/Getty Images hide caption

A U.N. military truck patrols on the road linking Mangina to Beni, the current epicenter of the Ebola outbreak in Democratic Republic of the Congo. John Wessels/Getty Images hide caption

Mogadishu's free ambulance service was founded in 2006 by Dr. Abdulkadir Abdirahman Adan after he saw people bringing relatives to the hospital by wheelbarrow. Abdulkadir Abdirahman Adan hide caption