Looks interesting. Henrietta died in the 1950s, but while she was alive, a tissue sample was taken from her body. Before then, labs were not able to keep human tissue alive outside the body. But there was something different about her, and her cells lived, and are still alive today. They have been propagated for decades, and have produced hundreds of tons of tissue for research. They have been sent to space, and helped cure polio. Nearly all research using human tissue samples, even to this day, are conducted with her cells.
For decades, her family was not aware that the tissue was being used.
http://www.youtube.com/watch?v=wRrNjHYxP_o