UFO are an English rock band, formed in London in 1969. They became a transitional group between early hard rock and heavy metal and the new wave of British heavy metal. Over a career spanning 48 years, UFO have released 22 studio albums, 14 live recordings and 16 compilation albums, with several albums and singles (including their 1979 live album Strangers in the Night) in the UK and US Top 40 charts, and have sold over ten million records worldwide.