This collection uses primary sources to explore America's entry into World War I. Digital Public Library of America Primary Source Sets are designed to help students develop their critical thinking skills and draw diverse material from libraries, archives, and museums across the United States. Each set includes an overview, ten to fifteen primary sources, links to related resources, and a teaching guide. These sets were created and reviewed by the teachers on the DPLA's Education Advisory Committee.

In June 1941, German Chancellor Adolf Hitler violated a non-aggression pact with Josef Stalin and launched a massive invasion of the Soviet Union. This offensive, named “Operation Barbarossa,” was motivated by a desire to crush one of Europe’s last holdouts against Nazi domination as well as Hitler’s disdain for communism and the Slavic people. Additionally, Hitler sought to commandeer the Soviet Union’s natural resources, including natural oil and gas and vast agricultural areas of Ukraine that could serve as the Nazi “breadbasket.”

This collection uses primary sources to explore the Wounded Knee Massacre. Digital Public Library of America Primary Source Sets are designed to help students develop their critical thinking skills and draw diverse material from libraries, archives, and museums across the United States. Each set includes an overview, ten to fifteen primary sources, links to related resources, and a teaching guide. These sets were created and reviewed by the teachers on the DPLA's Education Advisory Committee.