"Above and Below" combines Mars, Earth and the subterranean. How did you come up with this unusual idea?

Photographs inspire me the most. My imagination functions better that way, rather than when I take my lead from formulated premises. In this case it was above all pictures by Joel Sternfeld; photographs of deserts and water parks taken in massive long shots yet with an air of the unnatural to them. They contain an element of the absurd. I also studied for a year at the San Francisco Art Institute as a Fulbright scholarship holder, where I gave much attention to ghost towns. This was during the same period when the earthquake hit Japan. While surfing in Santa Cruz a presumably contaminated streetlight bearing Japanese characters floated towards us. This experience was decisive for the broader context of "Above and Below".

In what way?

As a director I consider myself something of a hunter-gatherer. My concepts and ideas initially overflow. Then I set about filtering them. I search for contexts that are only visible at second glance. At the same time, simple processes fascinate me. The more archaic the better. It was from such jigsaw pieces that the journey in the film, one from Mars to Earth and beneath its surface, finally emerged.

The so-called tunnel-people play a central role in the film. How did you hear of them?

I often made trips from San Francisco to the surrounding areas. I wanted to leave the city for a few days and visited Las Vegas. I had meant to relax, but the stay made me feel like I am visiting a city on steroids. It was all a garish sensual-overload. I walked numbly through the streets and saw in a water tunnel a guy in a nightgown with a chessboard. I asked him if he d like to beat my ass in chess and we played… The idea for the film immediately became more tangible.

How did you come across your tunnel-people?

I made a seven-week research trip to Las Vegas. I met a journalist who had written about the tunnel-dwellers. I also studied old city plans of the tunnels and went off on my own to look for possible protagonists.

How dangerous was that?

Let's put it this way, I wouldn't necessarily rush off to do it again. Inflamed by my idea I recklessly entered situations that might have turned out differently. Lots of the tunnel-people are very nice but also heavily addicted to crystal meth, which makes them unpredictable. When a guys ax emits sparks on the wall while he is running towards you, than you should probably go back and know that he won’t talk to you. On the other side there were so many people who welcomed me with open arms. I met my protagonist Lalo, for example, in one of the tunnels in which neither the journalist nor a city social worker had entered. I could hear Lalo growling "Who is it?" in the distance. Later, when filming, he told me that he was a former electrician and cage-fighter who was responsible for the death of two people "because of a stupid accident". Our equipment, rented from the school was pretty costly. So of course there was a certain uneasiness, particularly when Lalo wanted to know how expensive such a device might be. I think, however, that this recklessness was taken as bravery and won us respect, beside the fact that I was very clear and honest to him from the first second on. He really respected that and was fascinated by our work mentality to give him a voice and face. The research phase and shooting were intense. I hope this is apparent in the film. It's important for me to share experiences so viewers feel they experienced them, too.

Did the police always just let you be?

I was arrested twice. Of course the possibility had crossed my mind, since during research and filming I was perpetually entering fenced-off territory. And I was aware, too, that trespassing is a serious offence in America.

How did this come about?

We parked our transporter next to a tunnel and lugged a camera crane in black bags down into it. Somebody observed us and assumed that we were smuggling dynamite and weapons since under the tunnel there was a second one running between two banks. The police, once summoned, pushed us up against a wall and searched us. The interesting thing was the police officer shouted at me irritatedly, why don't you shoot your film in Berlin? There are homeless there, too! Fortunately the officers were informed at that very moment of an ongoing armed robbery and headed out. That was more important than our case.

How important then is the topic of homelessness in the film?

Of course "Above and Below" does deal with poverty and homelessness or lets say about finding a/your home. If my last film, "Battle of the Queens", can be seen as a film about homeland, then I have now made a film about “not having a home”. But nothing could be further from my actual aim than explaining America and its society to Americans. I didn't approach the film thematically, but rather conceptually, although the focus is definitely on individuals. To me it was about cowboys, ghosts and aliens. The idea was to make a film leading viewers from Mars down to Earth, and thence into its bowels. The film might equally have played out in the desert of Dubai. Or in China. But try telling that to a furious police officer!

Could the film have been shot in Switzerland, too? Was that ever considered?

No, the film could not have been made in Switzerland. There is always something adventuresome about filmmaking. And I shot my last two films in my homeland, Wallis, the Southern alps of Switzerland. It was time to move on and leave my garden behind me. Furthermore there is a keyword for this film, an important one: DESERT. Aridity. The visual beauty of death and destruction. I found optimal conditions in America to deal with the themes, circumstances and socio-political views that interest me. After all, the film lives from these people and their bleak biographies, and these led me through its making.

How are your protagonists now?
Most of them are doing really well. The film has changed the life of the crew but definitely also the protagonists/heroes lives. I am very proud and grateful for that. It was so important to me to show them film on the big screen, with an audience in the theatre. That’s what we did on our US theatrical tour and it turned out really well. I'm still often in contact with Rick and Cindy, they are both clean now and work as teachers in a rehabilitation facility for drug addicts in Texas. The film became part of their teaching program. Among the Mars-crew I'm most frequently in contact with April. She finished her geology studies and is continuing in research, put her Mars Dreams a little aside though. Dave is still in the desert but through the NYC premieres of Above and Below in contact with his daughters. They came to watch the film. Dave once called me after having swapped his old camper for a mobile phone. I'll visit him soon. Things aren't looking so good with Lalo. I don't know if he's still alive, he had potentially fatal abscesses back then and was in beaten-up shape. I hope for the best.

How did you come upon the peculiar Mars-Society?

At San Francisco Art Institute I saw a picture in a magazine of a lonely astronaut in a red desert. I was confused since I knew that no one could be there. When I looked more closely I saw a garden hose, and that was how I met the Mars-Society, a non-profit organisation working towards exploring and colonising the red planet. Scientists, fans of space travel and a couple of millionaires founded the society in the 90s. I was interested by the science behind it, but the real attraction was the absurd look of the Mars people and their passionate equipment. And at the same time the terrain on which they simulate Mars expeditions is of a poetically wistful abandonment.

You rejected the classic talking-heads structure in your documentary. Why?

My intention and aim was to keep my protagonists un-coerced and at their ease in conversation. For this film I didn’t like classical interviews or Q and As. I prefer conversations. Which doesn't mean I don't appreciate well-lit faces and spaces, but I try not to employ them at any cost. I tell my team approximately where I want to arrive, but spontaneity and flexibility are important for me, too. I think talking-heads are a matter of taste and don't suit every content. In "Above and Below" the audiovisual level was at least as important to me than precise statements.

The film uses a conspicuously large amount of music

There are almost 70 minutes of composed music in total. The soundtrack leads the way through the film. It was created in part before shooting, using photos and sounds that I brought back from my research-trips. This meant that we could already use music while shooting. It was apparent to me during research that music plays a very important role, since some of the protagonists do play instruments – Dave, say, with his drum set in the middle of the desert wastes.

Lots of people know your abundantly prize-doted short, "It's me.. Helmut". What parallels, if any, do you see to "Above and Below"?

The short was a twelve-minute fictional project and "Above and Below" a two-hour cinema documentary. But both films are about life and death and transience. Everything is beautiful yet, equally, destroyed. Both films feel a little tragicomic and play by-and-large outside, in nature. In the one, it's the mountains, in the other, the desert. And in both films I attempted to use sound and image to make cinema into adventure. In "Helmut" the backdrop vanishes, with "Above and Below" it's swept away.

"Above and Below" is your film school graduation film. Will you remain faithful to documentary-making?

I very much enjoy documentary-making. It broadens my horizon. And the extremely intensive research periods are something I don't want to do without. But as for fiction, I'm certainly not excluding it. Because at a formal level, feature films generally inspire me more than documentaries. I can probably say that I am interested in existential themes in a bare landscape and that I guess could probably be in the fiction field also quite interesting.