The concentration camp at Buchenwald opens. 1938 March 13 German troops enter Austria. July 23 Nazis declare that all Jews over the age of fifteen must carry identification cards at all times and present them upon request or inquiry from any police officer. All Jewish students are expelled from the German education system. The law remains in effect until Germany's 1940 invasion.
Nazi troops enter Czechoslovakia.
September 1 World War II begins, as Germany invades Poland, the country with the largest Jewish population in Europe. September 3 Great Britain and France declare war on Germany. The Soviet Union invades Poland. The first Polish ghetto is established in Piotrkow. November 30 Germany invades Finland.