Sometimes facts are just little pieces of trivia that we stack up, one atop the other. But sometimes a piece of knowledge comes along that shakes up all our preconceived notions about the ways of the world.

Whether it was a fact that made you finally understand a concept or a fact that contradicted a misconception of yours, tell us what it was and why it was so mind-altering in the comments.

Image: Helix nebula / NASA/JPL-Caltech.