The high concept “Powerslave” was Iron Maiden’s fifth studio album and a turning point in the band’s lyrical direction. Bassist Steve Harris wrote half of the album, pulling together stories and song ideas from history and legend. He wrote about ancient Egypt on the title track “Powerslave,” World War II fighter pilots on “Aces High,” the nuclear arms race on “2 Minutes to Midnight” and ol’ Western gun battles on “The Duellists.” His ideas reinvigorated the bands’ stories, pushing them away from usual subjects like the occult or violence. It’s a fun batch of clever, catchy songs with deep meaning that still appear on setlists today.