You wouldn't think there's much in common between prog-rock outliers Led Zeppelin and syrupy Scandi pop group ABBA, yet there is: Zep recorded tracks for their album 'In Through The Out Door' at ABBA's Polar Studios. According to legend, after meeting at the Stockholm recording studio, ABBA's Benny and Bjorn took Robert Plant on a night out to a local sex club. ¹⁾

Prior to his breakthrough with Led Zeppelin, Jimmy Page dabbled in the dark arts and even ran an occult bookshop and publishing firm, The Equinox Booksellers and Publishers on London's Kensington High Street. The four symbols on the fourth album's sleeve were supposed to be Satanic symbols. ²⁾

Before forming Zeppelin, each member of the band had a solid reputation as a session musician. As a result, when it came time to sign their first album deal with Atlantic, they were able to negotiate an unprecedented $200,000 advance as well as nearly entire writing rights to their music. ³⁾