A woman performs chest compressions on a mannequin while learning CPR on the steps of San Francisco City Hall. Justin Sullivan/Getty Images hide caption

itoggle caption Justin Sullivan/Getty Images

An unidentified western patient receives a stem cell treatment for heart disease at a clinic in Bangkok, Thailand on Feb. 7, 2007. STR/AFP/Getty Images hide caption

itoggle caption STR/AFP/Getty Images

This tiny telescope gets implanted in one eye and magnifies the image to make up for "holes" in the person's vision. It can greatly improve sight for some people with age-related macular degeneration. Courtesy VisionCare Ophthalmic Technologies hide caption

itoggle caption Courtesy VisionCare Ophthalmic Technologies

When Jennifer Jones Austin was unable to find a bone marrow donor match, her family appealed to the public in ads shown in churches and on the Internet. Courtesy of The ICLA Da Silva Foundation hide caption

itoggle caption Courtesy of The ICLA Da Silva Foundation