This article is a testimonial written by the first author regarding the research work performed with Drosophila between 1943 and 1959, at the Departamento de Biologia Geral of the Universidade de São Paulo (USP), which permitted the building of a nucleus of excellence. This research work, focused on the systematics and population genetics of the Neotropical species, began during the first of Dobzhansky's six visits to USP. Special attention was given to the multinational megaprojects conducted during his longer stays, from August 1948 to July 1949 and from June 1955 to July 1956. The role played by the Rockefeller Foundation is duly remembered, and so is the undeniable contribution brought by Dobzhansky, to the establishment of several laboratories dedicated to research in the field of natural population genetics and to the qualification of human resources. On the other hand, important "backstage" episodes are retrieved which were omitted in the official history and occurred from the planning to the execution of the project, carried out on the Angra dos Reis islands. Special attention was given to the relationship problems which resulted from Dobzhansky's, the leader's, difficult personality and contributed to the failure of the second and last multinational project.