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1974–1976: Sheer Heart Attack to A Night at the Opera

In May 1974, a month into the band's first US tour opening for Mott the Hoople, May collapsed and was diagnosed with hepatitis, forcing the cancellation of their remaining dates. While recuperating, May was initially absent when the band started work on their third album, but he returned midway through the recording process. Released in 1974, Sheer Heart Attack reached number two in the UK, sold well throughout Europe, and went gold in the US. It gave the band their first real experience of international success, and was a hit on both sides of the Atlantic. The album experimented with a variety of musical genres, including British music hall, heavy metal, ballads, ragtime, and Caribbean. May's " Now I'm Here " documented the group's curtailed American tour, and "Brighton Rock" served as a vehicle for his regular on-stage solo guitar spot. Deacon wrote his first song for the group, "Misfire", while the live favourite " Stone Cold Crazy " was credited to the whole band. Mercury wrote the closing number, "In the Lap of the Gods", with the intention that the audience could sing along to the chorus when played live. This would be repeated later on, more successfully, in songs such as "We Are the Champions.

The single " Killer Queen " was written by Mercury about a high-class prostitute. It reached number two on the British charts, and became their first US hit, reaching number 12 on the Billboard Hot 100. The song was partly recorded at Rockfield Studios in Wales. With Mercury playing the grand piano, it combines camp, vaudeville, and British music hall with May's guitar. "Now I'm Here" was released as the second single, reached number eleven. In 2006, Classic Rock ranked Sheer Heart Attack number 28 in "The 100 Greatest British Rock Albums Ever", and in 2007, Mojo ranked it No.88 in "The 100 Records That Changed the World". It is also the second of three Queen albums to feature in the book 1001 Albums You Must Hear Before You Die.

In January 1975, Queen left for a world tour with an upgraded light show. They toured the US as headliners, and played in Canada for the first time. Several dates were cancelled after Mercury contracted laryngitis. The band then toured Japan from mid-April to the beginning of May. They were greeted by thousands of screaming fans, and played eight times in seven cities. Despite the success, Queen were still tied to the original Trident deal and wages. They were all living in relative poverty in bedsits, while Deacon was refused money for a deposit on a house. EMI contacted lawyer Jim Beach, who tried to find a way of extracting them from their contract. Trident complained that they had invested £200,000 in Queen and wanted their money back first. In August, after an acrimonious split with Trident, the band negotiated themselves out of their contract and searched for new management. One of the options they considered was an offer from Led Zeppelin 's manager, Peter Grant, who wanted them to sign with Led Zeppelin's own production company, Swan Song Records. The band were concerned about being a lower priority than Zeppelin and Bad Company (also signed to Swan Song) and instead contacted Elton John 's manager, John Reid, who accepted the position. Reid's first instruction to the band was "I'll take care of the business; you make the best record you can".

Queen started work on their fourth album A Night at the Opera, taking its name from the popular Marx Brothers movie. At the time, it was the most expensive album ever produced, costing £40,000 and using three different studios. Like its predecessor, the album features diverse musical styles and experimentation with stereo sound. Mercury wrote the opening song " Death on Two Legs ", a savage dig at perceived wrongdoers (and later dedicated to Trident in concert) and the camp vaudeville "Lazing on a Sunday Afternoon" and "Seaside Rendezvous". May's " The Prophet's Song " was an eight-minute epic; the middle section is a canon, with simple phrases layered to create a full-choral sound. The Mercury penned ballad, " Love of My Life ", featured a harp and overdubbed vocal harmonies.

He knew exactly what he was doing. It was Freddie's baby. We just helped him bring it to life. We realized we'd look odd trying to mime such a hugely complex thing on TV. It had to be presented in some other way.

—Brian May on Mercury writing " Bohemian Rhapsody " and the groundbreaking music video.

The best-known song on the album, " Bohemian Rhapsody ", originated from pieces of music that Mercury had written at Ealing College. Mercury played a run-through of the track on piano in his flat to Baker, stopping suddenly to announce, "This is where the opera section comes in". When the rest of the band started recording the song they were unsure as to how it would be pieced together. After recording the backing track, Baker left a 30-second section of tape to add the operatic vocals. Reportedly, 180 overdubs were used, to the extent that the original tape wore thin. EMI initially refused to release the single, thinking it too long, and demanded a radio edit which Queen refused. Mercury's close friend and advisor, Capital London radio DJ Kenny Everett, played a pivotal role in giving the single exposure. He was given a promotional copy on the condition he didn't play it, but ended up doing so fourteen times over a single weekend. Capital's switchboard was overwhelmed with callers inquiring when the song would be released. With EMI forced to release "Bohemian Rhapsody" due to public demand, the single reached number one in the UK for nine weeks. It is the third-best-selling single of all time in the UK, surpassed only by Band Aid 's " Do They Know It's Christmas? " and Elton John 's " Candle in the Wind 1997 ", and is the best-selling commercial single (i.e. not for charity) in the UK. It also reached number nine in the US (a 1992 re-release reached number two on the Billboard Hot 100 for five weeks). It is the only single ever to sell a million copies on two separate occasions, and became the Christmas number one twice in the UK, the only single ever to do so. It has also been voted the greatest song of all time in three different polls.

"Bohemian Rhapsody" was promoted with a music video directed by Bruce Gowers, who had already shot several of Queen's live concerts. The group wanted a video so they could avoid appearing on the BBC's Top of the Pops, which would clash with tour dates, and it would have looked strange miming to such a complex song. Filmed at Elstree Studios in Hertfordshire, the video cost £3,500, five times the typical promotional budget, and was shot in three hours. The operatic section featured a reprise of the Queen II cover, with the band member's heads animated. On the impact of the "Bohemian Rhapsody" promotional video, Rolling Stone states: "Its influence cannot be overstated, practically inventing the music video seven years before MTV went on the air." Ranking it number 31 on their list of the 50 key events in rock music history, The Guardian stated it "ensured videos would henceforth be a mandatory tool in the marketing of music". Radio broadcaster Tommy Vance states, "It became the first record to be pushed into the forefront by virtue of a video. Queen were certainly the first band to create a 'concept' video. The video captured the musical imagery perfectly. You cannot hear that music without seeing the visuals in your mind's eye."

A Night at the Opera was very successful in the UK, and went triple platinum in the United States. The British public voted it the 13th-greatest album of all time in a 2004 Channel 4 poll. It has also ranked highly in international polls; in a worldwide Guinness poll, it was voted the 19th-greatest of all time, while an ABC poll saw the Australian public vote it the 28th-greatest of all time. A Night at the Opera has frequently appeared in "greatest albums" lists reflecting the opinions of critics. Among other accolades, it was ranked number 16 in Q magazine's "The 50 Best British Albums Ever" in 2004, a poll done in collaboration with British music and entertainment retailer HMV. It was also placed at number 230 on Rolling Stone magazine's list of " The 500 Greatest Albums of All Time " in 2003. A Night at the Opera is the third and final Queen album to be featured in the book 1001 Albums You Must Hear Before You Die. The second single from the album was Deacon's " You're My Best Friend ", which peaked at number sixteen on the US Billboard Hot 100, and went on to become a worldwide top-ten hit. The band's A Night at the Opera Tour began in November 1975, and covered Europe, the United States, Japan, and Australia. On 24 December, Queen played a special concert at the Hammersmith Odeon which was broadcast live on the BBC show The Old Grey Whistle Test, with the audio being later broadcast on BBC Radio 1. It became one of the band's most popular bootleg recordings for decades before being officially released in 2015.