Whether you use it every day or you've never even heard of it, Linux is undeniably important to computing history. It's been around in one form or another since the early 90s and continues to be a relevant player in the world of computing.

This year it turns 20.

It sprang into existence for a college student's thesis project and has grown into something used in computers around the world and even in your Android smartphone.

It's one of the greatest open-source success stories we've ever known.

Here's a recap of the "little operating system that could."