Well that’s the thing when they said, "Do you want to do this?" I said, "I don’t want to make a film that’s a tour of nostalgia. I'm interested in telling a story." What’s interesting is “Achtung Baby” was the point where the band reached a crisis point. Either they were gonna disband or reinvent themselves. They really were at that point where most bands break up. They had lost their sense of who they were. When they hit Berlin, it really was: Who are we and should we go our separate ways? To me, that was an interesting story. What came out of [Berlin] was a completely new band and a completely new sound. That album is a complete 180 degrees opposite from all their music before.

Bono has always seemed guarded. How did you get him to open up the way you did?

[Laughs] The very first thing I asked for was a lot of access and they agreed. They were on tour and they were in South America and I wanted to do these long interviews with each member of the band and sort of talk through that period. What you hear in the movie are these very intimate, very sort of vulnerable and raw [moments]. That became the source of the movie -- those interviews. I asked them to go back to the scene of the crime and meet me in Berlin for two days. They go back to [Hansa Studios] where it all blew up.

What happened when you met with them in Berlin and put them inside Hansa Studios?

I ask them to recount what happened. And they end up playing the key songs that they played on the album. They recount the traumatic moments that happened in that space. They hit a creative impasse in that building. They were not getting along and they talked very raw. In the movie, we recount where they found themselves.

There is an incredible moment where they talked about one song that wasn’t working [“Mysterious  Ways”] and Edge brought in a guitar part for the bridge section of the song and it wasn’t working. They start playing the bridge section, and that becomes the essential chorus for “One.” We found the session [DAT] tapes of them playing. It's pretty remarkable, like goosebumps on the back of your neck.

You have three films among the top 100 highest-grossing documentaries ever. What keeps you going in that medium?

Documentaries are really exciting right now. Where I think a lot of theatrical movies feel the same over and over again, documentaries seem to be changing and evolving. And the form keeps changing. This movie here is a very different kind of music documentary than you’ve ever seen. There’s a new type of story told. You’re seeing Bono perform a song acoustically by himself. You’ve never seen that before. You’re seeing footage you’ve never seen before.

Besides the five months you spent with the band on the road, you must have heard plenty of U2 in your lifetime. What records stick out to you? Any favorites?

My brother brought home the album “Boy” [when it came out in 1980]. I had never heard any music like that before. It was an energy and a tone in music I had never heard. It was shocking and challenging and beautiful. That’s what's good about U2. They keep evolving. And that’s what this movie is about. Some bands keep making the same music over and over again, but you like them because they are familiar. But U2 is always changing their sound and their music. That’s what makes them exciting and dangerous 40 years later.

The broadcast of “From the Sky Down” coincides with an expansive anniversary release of the disc on Monday.

There will be a handful of editions of the album, depending on a fan's budget. The most impressive? The Uber Deluxe Edition, which features six CDs, including the original album, its follow-up, “Zooropa,” B-sides and re-workings of previously unheard material recorded during album sessions; four DVDs including "From The Sky Down", the Zoo TV tour, a video anthology from “Achtung Baby” and bonus material; five 7" vinyl singles; 16 art prints from the album; an 84-page hardback book; a copy of Propaganda magazine; four badges; a sticker sheet … and a replica of Bono's sunglasses -- all for a cool $469.95.

British music magazine Q has also commissioned a tribute album to commemorate the anniversary featuring covers from Jack White, Depeche Mode, Patti Smith, Damian Rice, the Killers, Garbage and Nine Inch Nails. Both the anniversary release and the tribute album are available to order here.