In the modern age, libraries have become key guardians of cultural heritage and treasure troves of knowledge, and the Digital Collections of the City of Zagreb Libraries represent a significant display of technological development, digitization and enrichment of cultural heritage. This paper explores the digitized Zagreb heritage in the Digital Collections of the KGZ. The significance, content and impact of digital collections on the preservation and accessibility of Zagreb's cultural heritage are analyzed. The libraries of the city of Zagreb launched an ambitious project to digitize their materials in 2007, enabling access to digital replicas of original materials that document the history of Zagreb. The paper also explores the role of librarians in selecting materials for digitization and their role in the process. KGZ's digital collections provide a wealth of high-quality digital content, but there are needs to improve the user experience and revitalize digital exhibitions to attract a wider audience. This paper confirms the importance of the Digital Collections of the KGZ in the preservation and promotion of cultural heritage, at the same time highlighting the need for continuous improvements to ensure their continued relevance and accessibility to future generations.