Queen are an English rock band formed in 1970 in London by guitarist Brian May, lead vocalist Freddie Mercury and drummer Roger Taylor, with bassist John Deacon completing the lineup the following year. The band is noted for their musical diversity, multi-layered arrangements, vocal harmonies, and incorporation of audience participation into their live performances. Their 1985 Live Aid performance was voted the best live rock performance of all time in an industry poll. Queen enjoyed success in the UK in the early 1970s with the albums Queen and Queen II, but it was with the release of Sheer Heart Attack in 1974 and A Night at the Opera, the following year, that the band gained international success. They have released fifteen studio albums, five live albums, and numerous compilation albums. Eighteen of these have reached number one on charts around the world. The actual figure of Queen's album sales varies by source. According to an interview transcript on Brian May's official website, the band had sold in excess of 190 million albums by 2006. Following Mercury's death in 1991 and Deacon's retirement in 1997, May and Taylor have performed infrequently under the Queen name. Since 2004 they have been collaborating with Paul Rodgers, under the moniker Queen + Paul Rodgers As of 2005, according to The Guinness Book of World Records, Queen albums have spent a total of 1,322 weeks or twenty-seven years on the United Kingdom album charts; more time than  any other musical act including The Beatles and Elvis Presley.