"Urban Explorers" opens with a warning that what you are about to see is dangerous and legally questionable. It continues: "You could be fined, arrested, hurt, killed, or all of the above."
And then you enter the world of the urban explorers, such as this drain system under St. Paul.
"A lot of people would just think this isn't beautiful," says a man looking at the sodden ceiling. "But if you have seen some pictures I've taken, I'd say they are beautiful, and other people say that too. A lot of people don't get to see this, so it's a way to show them."
Filmmaker Melody Gilbert says she became hooked on the urban explorers after hearing a news story.
The St. Paul police had arrested some suspected terrorists breaking into a brewery. It turned out they were urban explorers, people who try to get into abandoned buildings or tunnels, just to see what's there.
She found some local explorers and persuaded them to take her along.
"We went into a drain," she says, then lets out a peal of laughter. "I still can't believe that I did all this."
Gilbert admits it took a fair bit of getting psyched up to go.
"But as I kind of went through the drain, and they started pointing out things like the brick on the wall and how the brick changes," she says. "When we went into a different part of the drain it changed. And you start to see the history even behind a drain, I got really interested in that."
That first "mission," as the urban explorers called it, set Gilbert on a journey across the U.S. and to Europe.
She clambered into disused NASA facilities in Florida, climbed through an abandoned asylum in Scotland, and even joined a dinner party in the catacombs under Paris. Along the way, she met people prepared to go to extraordinary lengths to pursue their hobby.
Take the two guys describing how they sometimes go through sewers to reach their objective.
"We keep ourselves pretty well protected to keep stuff from touching us," says one. "Whenever we go there we wear raincoats, chest waders, long rubber gloves that go up to our elbows, and it still doesn't feel like enough."
"It's kind of hard to walk though thigh-deep sewage, because it's all mucky and sticky down in the bottom foot or so," says the other. "Plus you are in liquid up to your waist, almost."
That last voice is Twin Cities-based Max Action, whom Gilbert describes as "the god of urban exploration."
"It's kind of hard to walk though thigh-deep sewage, because it's all mucky and sticky down in the bottom foot or so."
"He started in 1996, doing urban exploring with some friends over at the U," Gilbert says. "And he's sort of posting information about these missions that he did, and he's an amazing writer. And he started posting these stories and sharing them with people on the Internet, so because of that he got an international reputation for the kind of stuff he was doing."
Max Action says there are lots of reasons people enjoy urban exploring.
"There's a certain buzz that comes with getting out of a situation like that intact and unarrested."
However, he doesn't think that's the main draw. Some people do it to take unique pictures. Some like to delve into the minutia of where they are going.
"There's a lot of research, a lot of digging, scouting out, and a lot of really non-glamorous stuff that goes along with it," says Action. "It's not pure adrenaline. You know, there's quite a lot of more quiet moments that you have to be able to enjoy as well."
Max Action says he doesn't think the "Urban Explorer" film will encourage many people to get into urban exploration, but he does believe it's an interesting window on a very different world.
Both he and Melody Gilbert have been surprised at how many people comment on how stories of the urban explorers remind them of things they once did, going through old buildings, or exploring older parts of where they live.
Gilbert says it seems urban exploring may be changing, too. In France, she came upon groups taking it to the next level.
"This group in Paris actually created a cinema, an underground cinema, that was undetected by police for over a year, and they had parties and screenings and it was an amazing thing," says Gilbert.
As for screenings of "Urban Explorers: Into the Darkness," it's on the festival circuit now, including two shows this weekend at the Walker Art Center in Minneapolis.
Gilbert already has a television deal for the film, but she's keeping her fingers crossed for a theatrical distribution too.