Vials of smallpox are currently being tested in a high-containment laboratory at the CDC in Atlanta. On July 1, a lab worker at the National Institutes of Health found smallpox vials while cleaning out a storage refrigerator. Dr. Jon LaPook spoke with Steve Monroe, director of Division of High-Consequence Pathogens and Pathology at the CDC, about protocols of moving the vials and if the smallpox samples are still viable; and,Conservationist Yin Gang is overseeing an ambitious effort to save the artwork in ancient Buddhist caves. For centuries, blasting winds whipped deep into the caves and eroded the soft sandstone. But now pollution is the greatest threat.