World of Warcraft
"World of Warcraft" was first announced by Blizzard at the ECTS trade show in September 2001. Released in 2004, development of the game took roughly 4–5 years, including extensive testing. The 3D graphics in "World of Warcraft" use elements of the proprietary graphics engine originally used in "Warcraft III". The game was designed to be an open environment where players are allowed to do what they please. Quests are optional and were designed to help guide players, allow character development, and to spread characters across different zones to try to avoid what developers called "player collision". The game interface allows players to customize appearance and controls, and to install add-ons and other modifications.
World of Warcraft: Wrath of the Lich King
On September 19, 2012, the "Wrath of the Lich King" expansion was completely merged with the original "World of Warcraft" game, just as the "Burning Crusade" expansion was the previous year. Now all players who purchase the original game automatically receive "The Burning Crusade" and "Wrath of the Lich King" at no additional cost. This merging of the expansions with the original game is called a "Battle Chest".