A helicopter is unloaded from an LC-130 in Antarctica last December. Researchers on this mission were studying the Pine Island Glacier, one of the fastest-receding glaciers on the continent.
August Allen/National Science Foundation
Health officials around the world are on constant lookout for the deadly bird flu. Here a worker collects chickens on a farm in Kathamndu, Nepal, where the virus was suspected of infecting poultry last October.
Prakas Mathema/AFP/Getty Images
A worker makes a cut in the side of a sandstone block at the Cleveland Quarries facility in Vermilion, Ohio, earlier this month. The legal limit on the amount of silica that workers can inhale was set decades ago.
Ty Wright/Bloomberg via Getty Images
Two chimps groom each other at the Save the Chimps facility in Florida. The National Institutes of Health owns about 360 chimpanzees that aren't yet retired and that are living at research facilities; new guidelines say most of its chimps should be retired.
Save the Chimps