The Nazi advance into Eastern Europe caused YIVO to move its operations to New York City. A second important center, known as the Fundacion IWO, was established in Buenos Aires, Argentina. All four directors of YIVO's research sections were already in the Americas when the war broke out or were able to make their way there. The organization's new headquarters were established in New York City. A portion of the archives were sent to Frankfurt to become the basis of an anti-Semitic department of the Nazi's planned university. In 1946, the U.S. Army recovered these documents and sent them to YIVO in New York.