Free/Open Source Software is now everywhere, but the risk of losing forever some of it is growing. Shutdowns of once popular forges are early warnings that we should not underestimate. How many million lines of code would we lose if development hubs that are hype today were to disappear 20 years from now? This talk will present Software Heritage, whose aim is to collect, preserve, and share all publicly available source code. Forever. Software Heritage has already archived 3 billion distinct source code files and 650 million commits, spanning more than 25 million development projects.