Information about the title: Suitable for the introductory phase of the new upper secondary school in G9. From the 20th to the 21st century - a turning point? (Core module) Transformational societies in Eastern Europe since 1980: The upheavals in Poland and Romania in comparison (Elective module 1) The peaceful revolution in East Germany in 1989 (Elective module 4) European unification - a success story (Elective module 5) September 11, 2001 - a turning point in history? (Elective module 3) Afghanistan in global interest politics (Elective module 2) Information about the series: Source collections for history teaching in upper secondary education. The series is suitable for basic and advanced courses and sets new accents in competence orientation as well as in the integration of elective and advanced topics. The structure A brief introduction presents problems and backgrounds for each chapter. The detailed source.