Since the introduction of the original Xbox, Halo has been the franchise that helped put Microsoft on the map in the console game market. Today, the company announced that the series has racked up 50 million unit sales to date.

The strong sales of Halo 4, which now stand at over 4 million units sold, helped push the series' lifetime sales over the 50 million mark. Of course, given that Halo 4 raked in $220 million in its first 24 hours on sale, this shouldn't be a surprise.

The 50 million units sold includes all the main entries in the series, as well as 2009's Halo: ODST, Ensemble's strategy title Halo Wars, and the Halo: Combat Evolved Anniversary enhanced re-release.

To celebrate, Microsoft announced the Halo 4: Infinity Challenge worldwide tournament, which begins on December 17. If you win this worldwide tourney, you can nab yourself a 2013 Ford F-150 SVT Raptor truck, which features a UNSC-themed look. Even better, you could win the chance to have your digital, fully rendered likeness featured for two minutes in the next Halo game. For more information on the tournament, rules, and prizes, go to the Infinity Challenge site.

Via: Gamespot