The ever-expanding World of Warcraft

Welcome to Azeroth: Just a few of the playable characters from the original version of World of Warcraft Photograph: PR

The game's afoot: Early-level questing in Duskwood, just one of the regions in World of Warcraft Photograph: PR

Ready to cast: A player opens their character's spellbook. Most of the World of Warcraft characters have some kind of spellcasting ability Photograph: PR

Growth spurt: A "boss" character in the first World of Warcraft expansion pack, The Burning Crusade, which was released in January 2007 Photograph: PR

Take that: A Blood Elf Mage unleashes a "Frost Nova" spell. The Blood Elves were a new race of playable characters introduced in Burning Crusade Photograph: PR

Oh my god: In 2007, World of Warcraft had become so successful that it was parodied in an episode of South Park, called Make Love Not Warcraft Photograph: PR

Duel to the death: In the latest expansion pack, Wrath of the Lich King, players have access to a whole range of new siege weaponry and features to aid in combat Photograph: PR

Higher def: The game's designers have created a much more lush and green look for several of the the new regions in Wrath of the Lich King Photograph: PR

New kid on the block: Everyone is talking about the Death Knight, World of Warcraft's first hero class, introduced in Wrath of the Lich King Photograph: PR

Ice ice baby: A female spellcaster character in Icecrown Glacier, one of the colder regions of the new continent Northrend Photograph: PR