Collecting and analyzing online tourist reviews on destinations is important for sustainable tourism. These analyses can give insight into the extent to which natural and cultural assets in the destination are protected. These evaluations should be considered by the authorities as objective and realistic assessments. In this study, 4183 TripAdvisor reviews of foreign tourists visiting "Göreme National Park and Cappadocia Rocky Area", which is listed in the World Heritage Site, were evaluated. The data set consisted of English reviews of foreign tourists visiting the region between the years of 2018 -2020. Dictionary-based sentiment analysis, one of the text mining methods, was used in the study. According to the analysis results, the positive perceptions of the tourists about the churches, fairy chimneys, valleys and underground cities in the World Heritage Site were found to be significantly high (75%). Negative evaluations were found to be low (33%). In tourist reviews, 63% positive and 10.49% negative evaluations were made about the protection of the region. In addition, the awareness of the tourists about whether the locations they visit are World Heritage Sites was 30.6%. Tourists explained their negative opinions about the locations they visited with the words "extra_payment", "crowded", and "steep". Another finding of the study was that the area is adequately protected. There were, however, some concerns related to protection. The most striking aspects of protection concerns were those in which the words "painted" and "drawn" were used, an important indicator of visitor sensitivity to the protection of frescoes in rock churches. Since the destruction of natural and cultural assets in the region is unacceptable, recommendations are made to take the necessary measures to prevent such damage.