It was Halo 3's anniversary last week, but as popular as the game is, there's probably a few things you don't know about it. So thankfully GameSpot has a video covering 10 things you never knew about Halo 3..

The original Halo featured a poster of a cat called Jonesy who has gone missing, an obvious tragedy, and by the time Halo 3 rolled around, things didn't seem to be any different. In the Crow's Nest during the main campaign, you can find more posters of the missing cat, this time complete with a picture, to help you find the friendly feline. This itself is an obvious homage to the cat of the same name from Ridley Scott's Alien.

Jonesy isn't the only person missing in the Halo universe, as posters of one Jason Jones, a co-founder of Bungie, also crop up here and there, who was apparently last seen in Voi and New Mombasa. However, the most interesting way to find him is in the secret room of the seventh terminal. There's a specific room which, if you can get to a particular ledge, you'll find Jones chilling while shirtless, with his hands behind his head.

Both Halo 2 and 3 also feature some hidden backwards audio messages, which certainly set an ominous tone. The track Black Tower from the Halo 3 soundtrack features a message, which cryptically says, "Eyes from death's dream kingdom, appear as sunlight on a broken column, there in death's other kingdom, walking alone, trembling lips from prayers to broken stone." The messages are an homage to the poem The Hollow Men by T.S. Eliot, though out of context, provides a very uncomfortable atmosphere.

Check out GameSpot's 10 Things You Never Knew video above to hear some more pieces of trivia that you probably hadn't heard of before.