This study uses online reviews to explore memorable tourism experiences of tourists visiting different city attractions. Seeking to identify a collection of themes and concepts reflecting tourists' memorable experiences during their attraction visits, this study reveals the most shared tourism memories in cognitive-emotive-behavioral themes. By developing a matrix that categorizes tourist city attractions based on an ideographic approach, the study also argues that there are different types of tourist memorable experiences at different types of attractions (i.e., human-marker, nature-sight and human-sight tourist attractions). The findings extend previous understanding of the research in tourism experience and attractions by analyzing 156,986 TripAdvisor tourist reviews of the top ten most popular tourist attractions in London. This study also provides recommendations for destination management organizations and various city tourism stakeholders to plan, market and manage city tourism products and services.