Nothing cools off a boiling issue—such as immigration—like taking a spill in some hefty river rapids. In fact, this interview was delayed because filmmaker Ben Masters lost his cell phone, and other important items, after getting tossed from his canoe on the spectacular Rio Grande, which serves as the main character in his new film, The River and the Wall. The documentary, which premiered this spring at the South by Southwest festival, takes a trip along the river to see what’s at stake if a U.S.-Mexico border wall is constructed. It opens in select theaters May 2.

“I’ve gotten to spend a lot of time on the border in my life, but never did anything close to a 1,200-mile journey along it,” says Masters about the two-and-a-half-month adventure he took by horse, canoe, and mountain bike from El Paso to the Gulf of Mexico. “Every bend of the river, I was greeted with something new. I was surprised by the extent of the canyons and just the sheer amount of wildlife down there. The diversity of wildlife really was beyond my expectations."

Masters is the filmmaker behind Unbranded, an award-winning film that used outdoor adventure to examine the controversial wild horse overpopulation issue in the American West. For The River and the Wall, he was joined by National Geographic Explorer Filipe DeAndrade, ornithologist Heather Mackey, river guide Austin Alvarado, and conservationist Jay Kleberg. Both DeAndrade, who was born in Brazil, and Alvarado, who was born in the U.S. to Guatemalan parents, share their personal immigration stories.

You just got off a four-day float down the Rio Grande. How was it?

We had a great time, but I had a pretty bad canoe wreck. I got it pinned on a rock in the lower canyons. But that happens. We lost all of our food and my cell phone. Strong memories. I’m a glutton for this stuff.

You make adventure films that tackle big issues. Why did you want to tackle immigration?

I admit that if the Rio Grande wasn’t important to me, if the borderlands weren’t an important part of my life, I don’t know if I would have made this film because immigration policy isn’t something that I’m super passionate about. I’m more of a wildlife guy, but in order to talk about the border wall, you have to talk about immigration, because that’s the root issue of why the topic has come up. It goes beyond immigration for me. It goes into wildlife impact. It goes into private landowners. It goes into public lands and land access, and a lot of different things.

What is your personal connection to the Rio Grande?

Every summer during high school I worked on a ranch 10 miles from the border. When I was in college, I worked for four years every fall on a ranch right outside of Laredo (situated on the border). Then, in Texas, our big public lands playground is Big Bend National Park. That’s where we go to escape, to recreate, to float the river, to get a glimpse of what people in the American West are used to—these big, vast open spaces where everybody, regardless of their financial income, can go out and enjoy.

You and your team biked, canoed, and rode horses the 1,200 miles along the Rio Grande from El Paso to the Gulf of Mexico. Why do you choose to travel this way?

People want to know what’s going on at the border. The media doesn’t always do the best job of showing what’s going on, and people want to go and see it for themselves. Really, that was the impetus of the film. Like Unbranded, The River and The Wall is an adventure that goes into a controversial topic. But I think it’s good, in the sense that it’s a different way to talk about controversial issues, that really humanizes these big complex topics that you hear about. You can tell individual stories, and you can also make people not get defensive, or automatically assume that it’s biased because it’s on a particular news outlet. You quite literally take them on an adventure. It’s fun. It’s exciting.

As a native Texan, what were some of the things that surprised you about your home state on this trip?

I knew there were places where there are huge cliffs. But what I didn’t realize was the extent of those areas. It’s literally hundreds of miles of the border that has these massive canyons. I’ve been fortunate enough to go to the Grand Canyon, and see a lot of different national parks and really amazing landscapes in the American West. I was shocked to find that that kind of landscape in my home state.

In conservation, the point of view often seems to be tightly focused on protecting the wildlife and land but excludes or ignores the humans living nearby. Did you intend to bring both points of view together?

To make this film just about wildlife and wildlife habitat and not involve the human element would be a disservice to the complexity of the issue. We tried to show differing opinions on immigration and the border wall, both Republican and Democrat. Border Patrol was given a voice. We really tried to just let everybody speak for themselves, and allow the viewer to go on this visual journey, where they meet with people who actually live there, and make your own opinion on whether or not you believe a physical border wall should be contiguous, or just in stretches, or not there at all.

Two of your team members are immigrants: Filipe DeAndrade, who came to the U.S. from Brazil when he was five and became a citizen when he was 20, and Austin Alvarado, who was born in the U.S. to parents from Guatemala. Both sets of parents were undocumented when they arrived. How did those perspectives shape the story?

The stories of Austin and Filipe were kind of unraveled through production, and not really planned. Personally, I learned a tremendous amount about what it’s like to grow up either as an undocumented immigrant, or with parents who are undocumented. That’s just not an experience that I have in my life.

What's the main thing you hope viewers take away from the film?

I hope that people watch the movie and realize that the Rio Grande is not an expendable black line on a map that can be just discarded without a tremendous amount of impact and loss to the people who live there and to the wildlife that lives there. I understand peoples’ opinions of really wanting to find a solution to this legitimate humanitarian crisis, border security, and drug smuggling. Does a border wall even address them at all? An actual physical wall? Or is it kind of a distraction that takes people away from looking at what the root issues actually are?

Also, there’s a lot of optimism on the border, too. But you rarely see stories of hope in the news. There’s over a century’s worth of work on conservation down there, protected areas on both sides, lots of collaboration between the United States and Mexico. It’s a wonderful place.