Both the parks and historical fortifications constitute important components of urban green spaces in many cities around the world. The approach taken in terms of shaping these spaces often appears similar regardless of provenance. For this reason, recognising the preferences of their visitors is relevant from the perspective of creating and managing spaces that are not only safe, but also interesting. In this study we were interested in how fortress landscapes are perceived compared with typical urban parks in Poland. To this end, we conducted a questionnaire involving 117 participants who evaluated a set of 116 eye-level photographs (58 fortified landscapes and 58 urban parks environments). We analysed a range of correlations and mediation models, testing hypotheses regarding the mediating role of mystery, legibility and danger on preferences towards the two types of studied landscapes. We wished to establish what hidden mechanisms underpin the studied variables as well as their influence on the shaping of the researched landscapes. The results indicate that in the case of fortified landscape, it is important to maintain greenery favoured by the respondents, conducive to diversity and mystery while limiting perceived danger. Legibility can support educational values in the protection and maintenance of fortifications when sites are not devoid of mystery. In the case of park landscapes, legibility should not be improved at the expense of a complete loss of mystery, but should be accompanied by a reduction in perceived danger. In turn, mystery in parks plays an important role because without it, even legible park landscapes cease to be liked by the respondents. In turn, in fortress landscapes, mystery has a strong impact on preference, regardless of its relation to danger and legibility. At the same time, were it not for the fact that legibility reduces sense of danger, legible fortress landscapes would not be liked. Therefore, our findings can support the successful restoration and maintenance of fortress landscapes especially when their function shifts and they need to be managed and maintained in a planned manner in modern green areas.