It's all part of the fight against a new virus which causes Asian Bird Flu.
Scientists in Atlanta have recreated the virus to find out how it turned into such a deadly bug.
They hope to stop Bird Flu in its tracks before a pandemic can begin.
Researchers say they won't let the old virus leave their Atlanta labs. But, they also say Spanish Flu can now be treated successfully with anti-viral drugs, and some people may be immune to this flu strain.