The dramatic changes in web-scale data center design in recent years can be seen in the evolution of the Internet infrastructure at Microsoft, which has been among the leading proponents of deploying servers on pre-fabricated modules rather than traditional data halls. The company says this shift has allowed it to deploy servers at a faster pace with lower cost. Each successive generation has sought to refine control of airflow and reduce energy consumption. These photos offer a look at Microsoft's process as it continued to innovate its design from traditional cabinets to shipping containers to custom modules that can live outdoors, as seen in Microsoft's newest data center campus in Virginia.