The visual dimension of cities has been a fundamental subject in urban studies. In the 1960s, Kevin Lynch showed that visual knowledge informs people's perceptions and influences their understanding of space, impacting how they navigate complex urban environments. Sixty years later, big data and artificial intelligence (AI) are revolutionizing how we move, sense, and interact with cities.

This paper reviews the literature on the appearance and function of cities to illustrate how visual information has been used to understand them. We introduce a conceptual framework, Urban Visual Intelligence, to show how new image data sources and AI techniques are reshaping the way we perceive and measure cities, allowing us to study the physical environment and its interaction with human dynamics and socioeconomic environment at different scales.