Some archives and special collections have digitized documents in their collections making them accessible to researchers around the world. Below are a few open digital archives with collections focused on the World War II era.
A selection of documents, facsimiles, and transcriptions of materials covering history in Europe. Arranged by nation and then organized by period of time (where possible). Includes resources from Germany, the United Kingdom, and Russia during the World War II period.
The University of Minnesota's Immigration History Research Center Archive includes digital collections relating to immigration, ethnicity, and race. Majority of collection is focused on first and second generation immigrants and displaced people from central, eastern, and southern Europe coming to the US.
From the European University Institute this site serves as an aggregator to other primary sources. For immigration/migration sources go to Browse digital repositories > Subject > Migration.
Digitized texts, images, videos, recordings and museum objects about migration to and from Europe. Materials from European cultural and scientific institutions.
A UNESCO project, this database contains multi-lingual primary source materials from countries and cultures around the world. Coverage: 8000 BCE to present.