Three teenagers—two soldiers and a civilian—were among the 50 million or more estimated casualties of the 1918 influenza A pandemic. The lungs of the three were saved, preserved in formalin for more than one hundred years, and are now being used to study the virus. Obtaining samples for the study is hard, and the team including Dr. Michael Worobey, UArizona evolutionary biologist and associate director of the BIO5 Institute, was able to secure a total of 13 lung tissue samples from people who died between 1900 and 1931. From specimens that were being housed in the Berlin Museum of Medical History and the pathology collection of the Natural History Museum in Vienna; three of them, all from 1918, contained influenza RNA. These organs are providing genetic clues as to why this flu virus took so many lives.