The popularity of Nazi zombies is cemented forever in video game sales history thanks to Call of Duty, as Activision announces more than two million downloads of the Call of Duty: World at War Map Pack 1.

Released in March, the first map pack for Call of Duty: World at War contained three multiplayer maps players and one Nazi zombie map, which players went crazy for. So crazy that the pack sold its first million within one week of release. Treyarch is all sorts of ecstatic.

“This is a huge milestone and we are so appreciative of our incredibly supportive community who continue to play and enjoy the game,” said Mark Lamia, Studio Head of Treyarch. “We’re hard at work on Call of Duty: World at War Map Pack 2 and look forward to delivering that in June.”

The second map pack, announced last week, ups the ante with three new multiplayer maps and one Japanese zombie map, which should drive another two million sales easy. People just love Zombies, Modern Warfare 2 anyone?

[Via Kotaku]