When Amazon S3 launched in 2006, its design requirements fit one page: scalable, reliable, fast, inexpensive, simple, with no single points of failure. The system was built to treat component failure as normal and use scale as an advantage. Today those founding principles describe an architecture serving hundreds of millions of requests per second across tens of millions of drives, maintaining eleven nines of durability while shipping features without downtime. Hear S3 principal engineers trace the decisions from single host to strong consistency at global scale, how formal methods verify correctness, and how the team balances innovation with operational safety.