Research on the distribution of collective memories in national populations has often been conducted in relatively stable societies, where most individuals have experienced a limited range of event types. We examine collective memories in Lithuania, a society that has seen substantial change, using three surveys conducted during the two decades since Lithuanian protests against Soviet rule began in the late 1980s. We identify two types of events that individuals may recall, drawing on Sewell's () distinction between structure-transforming events and other events that are significant but less momentous, and we find that the two types of events exhibit different patterns of change over time: in particular, transformative events may absorb other events through assimiliation and are likely to be the focus of commemoration. Recall of transformative events also shows a distinctive relation to birth cohort. Our results support the need to take into account the nature of events in order to understand which events are remembered as important and by whom.