Workers with the aid group Doctors Without Borders prepare a new Ebola treatment center near Monrovia, Liberia, on Sunday. The facility has 120 beds, making it the largest Ebola isolation clinic in history. John Moore/Getty Images hide caption

itoggle caption John Moore/Getty Images

Kenyan health officials take the temperatures of passengers arriving at the Nairobi airport on Thursday. Kenya has no reported cases of Ebola, but it's a transportation hub and so is on alert. Simon Maina/AFP/Getty Images hide caption

itoggle caption Simon Maina/AFP/Getty Images

An outbreak of bird flu in India in 2008 prompted authorities to temporarily ban the sale of poultry. Diptendu Dutta/AFP/Getty Images hide caption

itoggle caption Diptendu Dutta/AFP/Getty Images

Early days: NASA's International Sun-Earth Explorer C (also known as ISEE-3 and ICE) was undergoing testing and evaluation inside the Goddard Space Flight Center's dynamic test chamber when this photo was snapped in 1976. NASA hide caption

itoggle caption NASA

With a comet fly-by and a solar orbit behind it, ISEE-3 has now revved its engines for a swing past the moon. Mark Maxwell/Courtesy ISEE-3 Reboot Project hide caption

itoggle caption Mark Maxwell/Courtesy ISEE-3 Reboot Project

A 6-foot-long electric eel is basically a 6-inch fish attached to a 5-1/2-foot cattle prod, researchers say. The long tail is packed with special cells that pump electricity without shocking the fish. Mark Newman/Getty Images/Lonely Planet Image hide caption

itoggle caption Mark Newman/Getty Images/Lonely Planet Image

By comparing "Skull 17" from the Sima de los Huesos site with many others found in the same cave, researchers were able to discern the common facial features of the era. Javier Trueba /Madrid Scientific Films hide caption

itoggle caption Javier Trueba /Madrid Scientific Films

DNA from these crab plovers, collected in Djibouti, Africa, should help scientists figure out how the unusual species fits into the family tree, says the Smithsonian's Helen James. Maggie Starbard/NPR hide caption

itoggle caption Maggie Starbard/NPR

The egg definitely came before the chicken in this case — the skeleton is from a modern adult kiwi, the egg from its much bigger, long-extinct cousin, Aepyornis maximus. Kyle Davis and Paul Scofield/Canterbury Museum hide caption

itoggle caption Kyle Davis and Paul Scofield/Canterbury Museum

Being able to insert the two man-made letters into DNA, alongside the usual four-letter alphabet, could teach old cells new tricks and lead to better drugs, researchers say. courtesy of Synthorx hide caption

itoggle caption courtesy of Synthorx