“Making Achtung Baby is the reason we’re here now,” Bono says early on in Davis Guggenheim’s new U2 documentary, From The Sky Down, which premiered at the Toronto International Film Festival on Thursday night. 

The film – which focuses on the tumultuous time in the band’s career 20 years ago – shows how Bono, guitarist the Edge, drummer Larry Mullen Jr. and bassist Adam Clayton got back on track: After considerable infighting and “creative differences” while the four hunkered down at Hansa Studios in Berlin in 1990 to try to make an album, the song “One” finally and miraculously sprouted from the unfinished “Mysterious Ways.”

“The movie has this pretty long [section] where you hear them write that song – and it’s goose bumps,” Guggenheim told Rolling Stone in Toronto. “The writing of that song really saved the band. They had come out of the height of Joshua Tree as the biggest band in the world. Rattle and Hum was a disaster from their point of view, a lot of bad reviews – they weren’t happy with what they had become. They take that bridge section out of ‘Mysterious Ways’ and they go back into the room at Hansa. They write a song on the fly in a matter of minutes. ‘One’ is written and the band is saved and we have all that on tape.”

There are other telling inclusions in the film, from footage of Bono getting angry in a dressing room after a Joshua Tree concert in 1987 (culled from Rattle and Hum director Phil Joanou’s amazing leftovers) to candid, present-day sound-only interviews that Guggenheim was able to draw from each band member. “The soul of the movie is these interviews I do with them,” he said.

“I didn’t know how they’d react to the things that I put in the movie,” said Guggenheim. “There are some very sensitive things. And to their credit, they said, ‘This is truthful; this is real; it’s not sensational.’”

The day after the TIFF gala screening, Bono, the Edge and Guggenheim spoke at a press conference about the film. “I found it a little humiliating to realize that we were so inept and these days we’re a better band,” Bono said. “We’ve learned our craft – and therein lies the huge danger, which is there’s a giant chasm between the very good and the great, and U2 right now has a danger of surrendering to the very good.”

Guggenheim had earned the Edge’s trust from the documentary they did together in 2008, It Might Get Loud, alongside two other guitar greats, Jack White and Jimmy Page. Still, it’s a relationship in progress, Guggenheim noted: “There’s a something adversarial about making a movie about something that neither side wants, but it’s naturally there.”

“For me, when Davis agreed to do this, I felt like I could relax because I knew the thing that he was most interested in was actually the truth as opposed to what was a great shot or what might be sensational,” said the Edge. “The stuff that’s in the film are those moments where we’re really being honest.”

“A little bit of sensationalism would have been good, a few great shots,” joked Bono. “I felt like I was mugged.”

In addition to the tension, intensity and struggle that plays out in the film, there is a lot of levity too, including a satirical montage of bands that have imploded or lost members, references and demonstrations of Bono’s unique gibberish singing, dubbed “Bongalese” and yes, the band in drag.

“What’s interesting is Larry really didn’t like the idea and thought he looked like he was in some skin flick,” said Bono. “Edge took to it with a perfectionist’s eye.”

 “I just freaked myself out because I looked so much like my sister, I was shocked,” the Edge said.

Added Bono: “Adam looked like the Queen of England and I looked like Barbara Bush.”