Iron Maiden formed in 1975 in Leyton, London, and having sold more than 100 million albums worldwide has become one of the most successful heavy metal bands of all time. They emerged in the early 80s as one of the frontrunners of the New Wave Of British Heavy Metal movement that had started in the late 70s, and their 1980 eponymous debut album reached number 4 in the UK. Their 1982 third album, The Number Of The Beast, was the debut of lead vocalist Bruce Dickinson, who replaced Paul Di’Anno. The LP is a major benchmark in the band’s long career, and also in the development of heavy metal. It topped the UK charts and sold millions of copies around the world, and has come to be regarded as one of the most influential metal albums of all time. Over the next few years they increased their reputation around the world with more albums that reached the upper regions of the charts in many countries, including the USA. Across 1984 and 1985 they completed their landmark World Slavery Tour, which saw them play to more than 3.5 million people, making it one of the largest tours of all time. The band's fortunes took a downward turn after Dickinson left in 1993. Although bassist Steve Harris has been the only constant member of the band, Dickinson is essentially their most important member, and his return to the group in 1999 sparked an inevitable upturn in record sales. Since then they have continued to delight fans with their classical music-inspired, guitar solo-drenched brand of heavy metal, and the new millennium has seen them produce some of their best work yet.