This chapter provides a detailed overview of the data center infrastructure underpinning warehouse-scale computers (WSCs), starting with the basics of data center infrastructure, the physical structure and layout of these facilities. It then delves into the critical power and cooling systems that keep WSCs running efficiently. Next we discuss the impact of cloud computing and AI workloads on data center design, highlighting the challenges posed by the increasing power density of AI hardware. We also explore the trade-offs between different power distribution architectures (AC vs. DC) and the role of uninterruptible power supplies (UPS) in ensuring continuous operation. We present case-studies of Google WSC power and cooling systems and data center design tradeoffs. We conclude with a retrospective of some key milestones thus far, and a discussion of some emerging trends including modularity, sustainability, and physical automation.