West Edmonton Mall first opened its doors to the public on 15 September 1981. The mall was developed in four phases, completed in 1981, 1983, 1985, and 1999. It was the largest indoor shopping centre in the world until 2004, and was named such in the Guinness Book of Records. The four phases of construction are used in a colour-coded system as a guideline for finding stores and attractions. The indoor roller coaster, The Mindbender had a fatal accident on 14 June 1986 when one of the rear cars derailed from the track and slammed into a nearby concrete pillar. Three people died and one was injured in the accident.