To address the challenges of dynamic web mapping under extreme load, CartoDB employs a caching system that leverages its content delivery network (CDN) and data storage to efficiently render live and changing data. By using cold hard cache, CartoDB can handle high loads by serving cached content on the CDN, while dynamic rendering servers only handle rendering as data updates invalidate the cached content. This approach enables CartoDB to scale dynamically and serve large volumes of requests, such as over 60,000 requests per second in a real-world testing scenario, with the potential to serve even more traffic.