For decades, mega-events have been employed as catalysts for urban development, transforming cityscapes, and generating socioeconomic growth. More recently, however, there has been a renewed focus on repurposing industrial heritage sites for hosting mega-events rather than relentless urban expansion. The concept of “eventful city” signals the importance of integrating mega-events into the existing urban fabric. While urban transformation resulting from mega-events is often accompanied by global narratives and social recomposition, industrial heritage reuse has gradually given importance to local communities and their collective memories in the face of contradictions such as gentrification and socio-spatial detachment. To reconcile these two tendencies, the role of collective memory in revitalizing industrial heritage driven by mega-events needs to be further investigated. This paper analyzes the social implications of mega-events on industrial heritage, particularly exploring the curation and use of collective memory in shaping urban narratives and public spaces. Using a case-study approach, it examines three distinct urban environments—Barcelona Eastern Coast, Torino Parco Dora, and Beijing Shougang compound. Descriptive literature served as the primary data source and was combined with critical studies to develop a topical analysis. The case studies present different ways of transforming industrial heritage into public space and investigate the evolution of the role of collective memory and local communities in this urban process. This paper concludes that while mega-events can significantly activate industrial heritage sites, what to remember, what to showcase, and what to include in terms of collective memory and lifestyle must be carefully considered.