'She's buying a stairway to heaven! 50 years of Led Zeppelin IV

The legendary album 'Led Zeppelin IV' was released 50 years ago this week and contains classic tracks such as 'Stairway to Heaven', 'Black Dog' and 'When the Levee Breaks'. It is Led Zeppelin's best-selling album and is seen by critics as one of the greatest records of all time. Did you know these facts about Led Zepp's iconic LP?

Led Zeppelin deliberately made sure that they did not include their names and faces on the cover – which featured a 19th century painting that had been bought by Robert Plant. Guitarist Jimmy Page said: "It was designed as our response to the music critics who maintained that the success of our first three albums was driven by hype and not talent."

Page decided that each member of the band could choose a personal emblem to feature on the album in place of a title. The rocker designed his own symbol but has never publicly disclosed any reasoning behind it – although it has been argued that it first appeared in the 16th Century to represent Saturn.

More than eight songs were actually recorded for the record but 'Down by the Seaside', 'Night Flight' and 'Boogie With Stu' failed to make the final cut. The latter would be featured on Led Zeppelin's sixth studio album 'Physical Graffiti' in 1975.

The tracks weren't all recorded at the same location as recording began at Island Records' Basing Street Studios in London before moving to Headley Grange in Hampshire. The change came about as Page wanted facilities where the group "could have a cup of tea and wander around the garden".

'Stairway to Heaven' is arguably the record's most famous track but it was claimed in 1982 that the song contains a hidden Satanic message in the lyrics when played backwards. Led Zeppelin's record label Swan Song Records denied the claims, saying: "Our turntables only play in one direction – forwards."

Led Zeppelin weren't actually the first artists to record a song named 'Stairway to Heaven' as they were beaten by pop crooner Neil Sedaka – who used the name for a track on his 1960 album 'Neil Sedaka Sings Little Devil and His Other Hits'.

Led Zeppelin re-worked Memphis Minnie's 1920s Blues track 'When the Levee Breaks' but it proved challenging to record. John Bonham's drumming sections were recorded at Headley Grange but some parts were played in a different tempo before being slowed down to fit with the track.

The title of 'Black Dog' references a black Labrador Retriever that wandered around the Headley Grange studios during recording. The song was included in Rolling Stone's 'The 500 Greatest Songs of All Time' and topped Q magazine's list of the '20 Greatest Guitar Tricks'.

Jimmy Page came up with the idea for 'The Battle of Evermore' after picking up a mandolin belonging to John Paul Jones. The guitarist revealed that he and singer Robert Plant came up with the track on the spot, despite the fact that he had never even played a mandolin beforehand.

Only one live recording of the song has been identified as Led Zeppelin found the track very challenging to record. The track was named as the late John Bonham played with two drumsticks in each hand. Only two takes of the song were recorded as Page says it was "physically impossible" for Bonham to do it again.