Every AWS service is designed to be highly available, but a small number of what we call Tier 0 services get extra-special attention. Come hear lessons from how AWS has built and architected Amazon Route 53 and the AWS authentication system, designed to survive cataclysmic failures, enormous load increases, and more. We cover our approach to redundancy and resilience at the infrastructure, software, and team levels, and we get into how the teams tasked with keeping the internet running manage themselves and still keep up with the pace of change that AWS customers demand.