This Howard Hughes Medical Institute video features Nadia Rosenthal, senior scientist at the European Molecular Biology Laboratory, as she discusses recent discoveries concerning the location and characteristics of adult stem cells. Human tissues vary in their ability to heal and regenerate. The nervous system, for instance, has weak powers of regeneration, while the skin is quick to make new cells for repair. The heart is the most important muscle in the body and yet has feeble regenerative capabilities. But newly emerging research has increased our understanding of regeneration. Find out how cutting-edge research may change the way we approach stem cells.