Pink Floyd's In the Flesh Tour should be remembered for musical reasons: After all, it's the only time they performed a full version of 1977's Animals, their hard-hitting and political rock opus. Instead, it's famous for everything else: the inflatable pigs, the sheer size of the gigs and, most notably, the artist/fan disconnect that inspired their classic follow-up concept album.

The trek kicked off Jan. 23, 1977 — the day of Animals' release — with a European run that stretched through late March. Their North American leg, shorter but much more notorious, launched on April 22 at the Miami Baseball Stadium.

In the Flesh was, to be on-the-nose about it, the first major brick in The Wall.

Floyd's shows in the U.S. and Canada — again featuring Dick Parry (sax, keyboards) and Snowy White (guitar, bass) — continued their now-established live spectacle, with pyrotechnics and props accentuating the hugeness of their music. And the set list was by now set: the entirety of Animals and Wish You Were Here, with an encore of two The Dark Side of the Moon staples, "Money" and "Us and Them." (They did dust off early acid-rock favorite "Careful With That Axe, Eugene" for their May 9 show in Oakland.)

From the outside, it looked like the culmination of continued hard work, the band having ascended into international arena stars. But that success, ironically and inadvertently, became a thorn in their side: Singer and bassist Roger Waters grew increasingly uncomfortable throughout the tour, complaining onstage about everything from union spotlight operators to fans setting off fireworks.

The most infamous moment — actually moments — occurred during the tour's final spot: July 6, 1977, at Montreal's Olympic Stadium. One came at the end, during a second encore, as Floyd attempted to satiate a riled-up audience with a lumbering jam dubbed by fans "Drift Away Blues."

"We’re just gonna play some music to go home to," Waters told the crowd, somewhat awkwardly, before White cranked out a grinding guitar solo. (Notably, the group's full-time guitarist, David Gilmour, sat out and watched from the mixing board.)

Earlier came an interaction between Waters and a fan near the stage, culminating in the bassist firing off some spit. (Bootleg recordings floating around online supposedly document this exact altercation.) Asked by Howard Stern in 2012 why he responded with saliva, the singer — adopting fake outrage — fired back, "Because he was climbing up the front of the fucking stage!"

It was a sour final note.

"I just thought it was a great shame to end up a six-month tour with a rotten show," Gilmour told Musician in 1982. And White described the atmosphere, naturally, as "a bit funny": "It wasn’t very good vibes for some reason," he noted to Rolling Stone in 2020. "That was the show where I looked to my left and I could see Roger spitting at one of the audience members. I thought, 'What’s he doing? That’s not very …” [Laughs] I remember that."

They did walk away from this turbulent tour with one major positive, albeit a creative one: Waters had now planted the conceptual seed for what became Pink Floyd's final masterpiece.

"The idea for The Wall came from 10 years of touring with rock shows," he said in a 1979 radio interview. "Particularly the last few years — I think in '75 and '77 — when we were playing to very large audiences, some of whom were our old audience, who'd come to hear what we wanted to play, but most of whom were only there for the beer, in big stadiums. And consequently, it became rather an alienating experience doing the shows. ... I became very conscious of a wall between us and our audience."

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