In this talk, we explore how to construct resilient distributed systems on top of unreliable components. Starting, almost two decades ago, with Leslie Lamport’s work on organising parliament for a Greek island. We will take a journey to today’s datacenters and the systems powering companies like Google, Amazon and Microsoft. Along the way, we will face interesting impossibility results, machines acting maliciously and the complexity of today’s networks. Ultimately, we will discover how to reach agreement between many parties and from this, how to construct new fault-tolerance systems that we can depend upon everyday.