This project explores the historical thinking concept of continuity and change through a Grade 10 inquiry activity focused on the development of international cooperation following the First and Second World Wars. Using primary sources related to the League of Nations and the founding of NATO, students analyze how ideas surrounding peace, security, and international alliances both changed and remained consistent over time. Using guided primary sources and a continuity and change graphic organizer, students develop critical historical thinking skills by examining perspective, context, and historical patterns while building a deeper understanding of Canada’s role within the international community during the twentieth century.