Pandemic influenza viruses pose a significant threat to public health worldwide. In a recent Nature paper, Taubenberger et al. (2005) now report remarkable similarities between the polymerase genes of the influenza virus that caused the 1918 Spanish influenza pandemic and those of avian influenza viruses. Meanwhile, Tumpey et al. (2005) reporting in Science show that the reconstructed 1918 Spanish influenza virus kills mice faster than any other influenza virus so far tested.