This study reports on outcomes of an investigation of visitors’ long-term memories of the 1970 Japan World Exposition, Osaka. The paper reports in two parts the emergent outcomes of a study that provides understanding of the nature of visitors’ long-term memories of their experiences in an informal leisure-time con­text. First, the paper discusses the common and most dominant recollections that emerged from 48 visitors’ memories of this event 34 years ago. An overall explica­tion of visitors’ memories of their experiences of the event reveals an interesting mix of reactions: wonderment about the world and the amazing technological advances of the era, blended with personal discomfort and frustrations associated with the memories. These mixed feelings are presented against the backdrop of Japanese na­tional identity re-emergent on the world stage. Second, an analysis and discussion of qualitative data provides case examples of how three psychological and behavioral factors (affect, agenda fulfillment, and rehearsal) shape the vividness of episodic and/or autobiographical memories of the episodes as they are recalled 34 years later. This paper vividly illustrates the power of qualitative data to illuminate understand­ing of visitors’ long-term memories and presents some significant issues for museum staff to consider as they plan for visitor experiences that will have lasting impact.