In this chapter, we review key place-based theories that have conventionally been used to understand crime patterns at risky places. We review salient ideas that have informed our knowledge of risky places, linked to patterns in place and time, the interaction between people and their environments, and why and how factors converge at particular places and times to develop concentrated pockets or opportunities for crime. We acknowledge how these can be considered at different scales, and we discuss why we break down risky places into three key elements: risky facilities, risky nodes, and risky pathways and journeys. We also explore some factors that make people feel unsafe in risky places. We then explore the principal components of systems thinking identified in Chapter 2 and consider how these can support and add value to conventional place-based approaches to preventing crime at risky places.