In this talk I walked through some real world use cases of large DDoS attacks and how Cloudflare infrastructure is built to handle the load from a technical perspective. I also provided and presented some technical examples and proof of concepts of simple DDoS attack vectors implemented in Python demonstrating the effect on a sample web server. This talk was given at The Financial Times for the London Web Performance meetup. Some slides in this talk have been redacted. Credit for part the content of this talk goes to Cloudflare.