As the internet, smartphones, and review platforms transform how travelers discover urban attractions, understanding this process is critical for harnessing a sustainable urban attraction space. Yet urban discovery remains poorly understood and existing research is fragmented. To address this gap, we adapt Leiper's tourist attraction systems framework to study urban discovery. Our grounded theory analysis on 126 interviews resulted in five distinct discovery modes: instrumental-rational, go-with-the-flow, social, flaneur, and habitual. Besides richly describing these modes, we identify personal, social, contextual, demographic, and affective factors influencing them. We illustrate how playful discovery modes—go-with-the-flow, social, and flaneur—are compatible, leading to mixed discovery modes, while the remaining modes are incompatible. These findings challenge the dominance of rational choice models by revealing a broader spectrum of discovery behaviors. They also provide a foundation for designing a more inclusive urban attraction content space and offer strategic implications for urban attraction management.