Before you see "Avengers: Endgame," here's a refresher on the entire history of the Marvel Cinematic Universe.

Our comprehensive timeline includes events both on and off screen, from the birth of the Infinity Stones to the Thanos snap.

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It all started with 2008's "Iron Man," but the Marvel Cinematic Universe actually stretches back millions of years.

The history includes far more than what we see on the screen. Thankfully, there's plenty of context within the 21 movies so far to give us a sense of just how far back it goes and when important events not seen in the movies take place.

It's all been leading up to this weekend's "Avengers: Endgame," the culimination of 11 years worth of MCU movies, which have grossed over $18 billion worldwide combined so far.

READ MORE: The Marvel Cinematic Universe will enter an uncertain era after 'Avengers: Endgame,' but experts see a path for it to dominate another decade of pop culture

We've put together a timeline that details the entirety of the MCU, based on the movies (we excluded events from television shows, like the Marvel Netflix series). The timeline can be confusing and isn't entirely concrete. We've included year ranges with each slide below to give a decent understanding of when events took place. Specific years that we know for sure are noted, as well.

From the birth of the Infinity Stones to the Thanos snap, the MCU has built an impressive timeline of events. We hope this timeline, which puts all major events (including ones you forgot about) together will help you better understand some characters' backstories and how specific events have shaped the universe so far before you see "Avengers: Endgame."

Carrie Wittmer contributed reporting to an earlier version of this timeline.

Check out our in-depth MCU timeline below: