Sgt. Pepper at 50: 20 fascinating facts about the Beatles' landmark album

It was 50 years ago today: the Beatles' groundbreaking album, Sgt. Pepper's Lonely Hearts Club Band, was released.

Long considered one of the greatest albums of all time, it both thrilled and perplexed fans with its use of unconventional sounds and studio wizardry — commonplace now, but at the time, it was revolutionary.

The album included some of the Beatles' most enduring hits, including "Lucy in the Sky with Diamonds," "When I'm Sixty-Four," "A Day in the Life" and the title track.

It also comes with some surprising facts — so to mark the anniversary, we've gathered 20 things you might not know.

1. The idea came to Paul McCartney on a plane

In November 1966, Paul McCartney was reportedly on a flight to London when he came up with the idea for a song involving an Edwardian military band — which marked the start of the Sgt. Pepper concept. In February the following year, after recording the song "Sgt. Pepper's Lonely Hearts Club Band," McCartney suggested creating an entire album by a fictional band.

2. Sgt. Pepper, however, arrived a little later

Sgt. Pepper himself, however, didn't appear until halfway through the making of the album, according to George Martin in his memoir, All You Need Is Ears. "It was Paul's song, just an ordinary rock number ... but when we had finished it, Paul said, 'Why don't we make the album as though the Pepper band really existed, as though Sergeant Pepper was making the record? We'll dub in effects and things,'" wrote Martin. "I loved the idea, and from that moment on it was as though Pepper had a life of its own."

3. Without the Beach Boys, Sergeant Pepper may never have happened

The Beach Boys' landmark album Pet Sounds had a huge influence on Sgt. Pepper, as the former album incorporated a host of sounds not normally found in pop music, and exemplified the role studio gimmicks could play. 'Without Pet Sounds, Sgt. Pepper never would have happened," remembered Martin in the liner notes to a Beach Boys box set. "Pepper was an attempt to equal Pet Sounds."

4. It also happened because the Beatles knew they wouldn't have to play it live

In August 1966, the Beatles permanently retired from touring — so when they recorded Sgt. Pepper, they did it without having to worry about how they would play the songs live. This allowed them to introduce all kinds of instrumentation and effects.

5. The iconic album cover includes leaders and luminaries — but some didn't make the cut

The album cover collage was designed by pop artists Jann Haworth and Peter Blake, who won a Grammy for the artwork. Luminaries on the cover include Mae West, Lenny Bruce, Edgar Allan Poe, Bob Dylan, Carl Jung, Aldous Huxley, Marilyn Monroe, Karl Marx, James Joyce, Oscar Wilde, Lewis Carroll and dozens of others. Objects on the cover include a statue from John Lennon's house, a garden gnome, a Sony TV set, a hookah and a cloth doll — as well as wax figures of the Fab Four borrowed from Madame Tussauds. People who were supposed to be on the cover but were later removed included Mohandas Gandhi, Adolf Hitler and Jesus Christ.

6. Two hits also didn't make it onto Sgt. Pepper

The first two songs recorded for the album were "Strawberry Fields Forever" — which the group spent a record 55 hours in studio recording — and "Penny Lane," but EMI pressured the group to release them as singles. Martin and manager Brian Epstein didn't think it was right to make fans pay twice for the songs, so they left them off the Sgt. Pepper album. Martin would later call the decision "the biggest mistake of my professional life."

7. Fans didn't have to open the album to read the lyrics

For the first time in pop music history, the album's lyrics were printed on the back cover.

8. Martin did far more than produce and mix the album

"Fifth Beatle" Martin was not only the album's producer and mixer; he also played harpsichord, Lowrey organ, glockenspiel, Hammond organ and piano on the album, and was behind many of the tape loops and sound effects. He also co-arranged and conducted the string, percussion and horn sections.

9. The groundbreaking album was recorded on a 4-track.

Sgt. Pepper was recorded on four-track equipment. At the time, eight-track equipment was widely used in the United States, but didn't hit London's commercial studios until late 1967. As a result, the engineers used a technique called reduction mixing, where they would record the four tracks, mix them down, then use those tracks alongside others. The same technique was used on albums including Pet Sounds and Jimi Hendrix's Are You Experienced, both released around the same time.

10. The album uses all kinds of studio wizardy — including flanging before it became flanging

The album incorporates all kind of studio techniques, among them signal processing, dynamic range compression, reverb, pitch control and ambiophonics — and Martin unwittingly created a new name for a particular technique. He used automatic double tracking, or ADT, to double the vocals, giving them a richer, fuller sound. (Before this, vocalists would have to sing the track twice.) Martin joked to Lennon that his voice had been treated with "a double vibrocated sploshing flange with double negative feedback," and from then on, Lennon called the effect "flanging." The term is still used in audio production today. 

11. Sgt. Pepper wasn't actually released June 1

The album was scheduled for release in the U.K. on June 1, 1967, but it ended up being given a rushed release on May 26. It was released in the U.S. on June 2. Still, June 1 is considered the official release date.

12. Not all the Beatles appreciated the concept

McCartney liked the fictitious band concept, but not all of the Beatles were onboard. George Harrison said he wasn't a fan of the idea, or McCartney's approach. "A lot of the time it ended up with just Paul playing the piano and Ringo keeping the tempo, and we weren't allowed to play as a band as much," he later said. "It became an assembly process — just little parts and then overdubbing — and for me it became a bit tiring and a bit boring."

13. It took a lot of time and a lot of money

According to sound engineer Geoff Emerick, the band spent roughly 700 hours making the record — 30 times more than the time they spent on their first record, Please Please Me. The album reportedly cost £25,000 to produce — more than 60 times the cost of their first.

14. Dogs get an added bonus

When the album runs out, listeners go into a loop of random voices and noises — but Fido gets an added bonus: a tone so high-pitched that only dogs can hear it.

15. The BBC banned several of the songs 

The BBC banned several songs, including "A Day in the Life," "Lucy in the Sky with Diamonds" and "Being for the Benefit of Mr. Kite!" because of the perception they're about drug use. But while many believed "Lucy in the Sky with Diamonds" was about LSD, Lennon insisted that it was inspired by a drawing by his son Julian, then just four years old.

16. That famous cheer is from a Beatles concert

The crowd cheer leading into "With a Little Help from My Friends" was recorded during a Beatles concert at the Hollywood bowl.

17. There's an order to the animals

"Good Morning Good Morning" was inspired by a TV commercial for Corn Flakes, and at the end, there is a series of animal noises. At Lennon's request, the animals appear in a specific sequence: with each one large enough to devour the last.

18. The apostrophe is supposed to be there

For decades there has been great debate over whether Sgt. Pepper's is supposed to have an apostrophe or not, because the album title has one; on the album's cover, however, Ringo Starr's drum kit does not. According to co-designer Haworth, the apostrophe was supposed to be there. "It was a mistake. There should have been an apostrophe," she said. "Sgt. Pepper is the man — and the band belongs to him."

19. The album was a hit from the start

Sgt. Pepper was an enormous chart hit. It spent 27 weeks at the top of the U.K. albums chart, and 15 weeks at the top spot in the U.S. It also won four Grammys in 1968, including album of the year — the first rock record to do so. The album remains one of the best-selling of all time, and this week, it has once again pushed its way back to the No. 1 spot on the U.K. charts.

20. Most of the critics loved it — but not all of them

Overall, the album was well-received by critics, but there were exceptions — most famously the New York Times review by pop critic Richard Goldstein. "The sound is a pastiche of dissonance and lushness," Goldstein wrote. "The mood is mellow, even nostalgic. But, like the cover, the overall effect is busy, hip and cluttered," he continued, calling the future classic "an album of special effects, dazzling but ultimately fraudulent."

Rolling Stone writer Langdon Winner clearly saw the album differently: "The closest Western Civilization has come to unity since the Congress of Vienna in 1815 was the week the Sgt. Pepper album was released," he wrote. "In every city in Europe and America the radio stations played [it] ... and everyone listened ... it was the most amazing thing I've ever heard. For a brief while the irreparable fragmented consciousness of the West was unified, at least in the minds of the young."

This Friday, June 2, join Radio 2 Drive host Rich Terfry on a deep dive into the Beatles as one of their most legendary records turns 50. Hear Sgt. Peppers Lonely Hearts Club Band in its entirety, plus more songs and stories, this Friday at 6 p.m. (6:30 NT) on Radio 2 Drive.

​— Jennifer Van Evra, q digital staff