In one of the most intense filmmaking experiences imaginable, actors Heather Donahue, Joshua Leonard, and Michael C. Williams played fictionalized versions of themselves, heading out to the Maryland woods to film a documentary about the legend of the Blair Witch. Part of what made The Blair Witch Project so groundbreaking is that you never see the actual Blair Witch, and the filmmakers didn't use special effects to scare audiences; instead they had genuine reactions from a cast that didn't know what awaited them in the woods. The film managed to do so much with so little, and it also introduced one of the first viral marketing campaigns, gaining a following before it even hit theaters. The Blair Witch Project turns 20 this week, so we spoke to the cast and crew to look back at the making one of the most legendary horror films of all time.

Made with a budget of only $60,000, the film premiered at Sundance in 1999. Just hours after the midnight screening, the two young directors sold the film to Artisan Entertainment for $1.1 million. The movie was the most-talked about horror movie of the season, but it took years to become a reality. Though Sanchez and Myrick first came up for the concept as film students at the University of Central Florida in 1991, they put their plans into action in 1996, and due to funding issues, they didn't start casting the film until 1997. Sanchez and Myrick had to find actors who were quick on their feet, because although the duo had written a very detailed outline of the script, the dialogue would be almost entirely improvised.

In 1997, Eduardo Sanchez and Daniel Myrick sent out three unknown actors to improvise a horror flick in the woods and film it on their own. The concept was practically unheard of, and it wouldn't be easy to pull off. But two years later, Sanchez and Myrick had a bonafide hit on their hands with The Blair Witch Project, which inspired a new horror subgenre and became one of the most iconic horror flicks of all time.

Daniel Myrick : We set up the audition process in such a way that allowed us to quickly assess a person's ability to improvise, and [when the actors signed in], they saw a paragraph that stated that you are going up for parole, you were convicted of murder twelve years ago, and now you're getting ready to state your case in front of the parole board.

Michael C. Williams ["Mike"] : I didn't really have any professional experience, other than training at SUNY New Paltz for four years. [The casting call] said "feature film to be shot in a wooded location," I think it said improvisational feature film... Improv and camping required. And I love both of those things, so I thought that was interesting. Improv? How do you improv a film? So I went to the open call and there was a sort of sign hanging before you went into the room, a little 8x10 flyers hung up like, "if you get this role you will be subject to uncomfortable physical situations, you will never be in harm's way, you will be outdoors most of the time, if this is not your thing, please don't audition."

During pre-production, the directors had to make sure everything was in perfect condition for the actors to shoot on their own. This involved teaching them how to use the equipment, familiarizing them with the town, and setting up survival tools.

Myrick : [Heather] was the only person out of the tons of people that I saw over the course of the year, that, when asked "Why do you think you should be released on parole," she looked at me dead in the eye and said, "I don't think I should be."

Eduardo Sanchez : [Heather] scared the crap out of us, and we were in this rehearsal space in New York City, the most un-scary situation we could be in.

Williams : Ed Sanchez was sitting behind a table with a couple of other folks [in the audition room], and he just said, "You've just served ten years of a twenty year prison sentence, you're up for parole, what do you have to say for yourself?" So he didn't watch my tape, he didn't say good morning, he didn't say anything, he just immediately went into improv.

Sanchez : Once they got to the woods, we wanted them to be as alone as possible, so we tried to train them as much as possible as far as filmmaking was concerned, and Mike, we ran him through a little audio course on how to connect the cords, how to make the audio good with the DAT machine.

Myrick : Our producer Gregg Hale, who was former military, turned us on to these GPS systems. We had two of them—the actors had one in their hand, and we had one, and three weeks prior to shooting, Ed and I went to the woods and marked all the areas where the campsites were going to be, and where we were going to pull off the gags, so it was all very methodically thought out.

Sanchez : We took them to Montgomery College to walk around a little bit, that was supposedly the place that they had met, and we drove them around Maryland, to give them the sights, to sort of give them an idea of what it's like to live there, and we got them magazines from the 1994 era so they could read up about it, and then for Heather, we worked on the mythology. We gave her a detailed kind of account because we felt she needed to know off-hand a lot more about the Blair Witch than the guys did, so we told her, "You need to become kind of an expert on all this information," and then obviously just the camping basics.

Leonard : I’d never shot with the CP-16 before. It was a beast of a camera—mostly used for news broadcasts before video was invented. When I arrived in Maryland, I was introduced to the late and great Neal Fredericks, who was in charge of the film’s "look." He and I went out shooting for a day so I could learn the ins and outs of the CP. But even that didn’t save me from screwing up a bunch of the footage—that whole conversation in the movie about feet versus meters after we left Mary Brown’s house—that was real. That was me realizing that I’d screwed up the calculations for my measurements and the footage was probably going to be out of focus.

Williams : I had to learn how the sound works, how the DAT works. Anything that was shot in the video camera, you're hearing it in the video camera, but any of the black and white stuff was all the DAT, which is an old school sound system.

Myrick : The bulk of the film was basically constituted the Hi8 camera and that is pretty much fire and forget. You roll it and it auto-exposes and does everything for you. That training process went on for a day or two.

Gregg was in charge of the whole waypoint GPS thing, the way we got them from one location to the next in the woods without leading them. He had to give them a lesson in how to work the GPS tracker, just stuff like that, basic survival stuff, basic safety things, like if something happened what would you do.

Myrick : They would get to a way-point on their GPS, and they would see that milk crate, and we had a bicycle flag sticking up, so they would know they were at the campsite, and that's when they were instructed to set up camp for that night. Inside the milk crate were tiny little film canisters where they would open up and have their own individual directing notes. So they were then told to read their individual directing notes and not tell each other what the other read.

Sanchez : We took them to the location, and we had to pack their bags, and we kind of set them at the beginning of the filming off on their own, and most of the time the only time we would talk to them was if something went wrong, or there was a big question that had to be answered immediately. We tried to follow them for the first few days, but that didn't work. It was just too hard staying out of their way, and also you couldn't do anything else. All you could do was watch them. We started watching the footage when we got back, and we liked what we saw, and we thought everything was working, so we kind of abandoned the idea of watching them. So it was mostly just kind of guiding them through the directing notes, and making sure that everything was going according to plan.

Myrick : We were able to kind of steer them through the woods without having a whole crew around them, but at the same time, give them directing notes to kind of guide their character.

Williams : The scenes were driven by notes that were left in 35mm film canisters throughout the woods, so we had a GPS that was programmed by the producers and directors, they had mapped out the whole locations. They pre-programmed what they called waypoints into the eight days. At each waypoint station, we would look at a GPS, and it would say, "waypoint number 3, waypoint number 4 is three km away," so you would look up in the compass and at the next waypoint there would be an event happening there.

Myrick : It was an eight-day shoot where they were really camping out in the woods. It was by design to push them and to elicit genuine response for them. Over time, we sort of rationed back their food so they were hungry. Obviously not starving or anything, but you get irritable whenever you're not eating full meals every day, so it was a little bit of this method kind of survivalist approach that we prepped them on in advance.

Leonard : The night I was supposed to leave, the filmmakers left me a note telling me to wait for everyone else to fall asleep and then sneak out of the tent. I remember it said “If anyone wakes up, tell them you have to take a piss and get out of there as quickly as possible.” After I snuck out, Ed, Dan and Gregg were there waiting for me. They threw me in the car and told me I was going home.

Leonard : People always ask if we were actually scared when the filmmakers messed with us in the middle of the night. The answer is not really... because what was usually happening behind the scenes was we were exhausted and hungry and often wet. We’d set up camp and crash, and just about the time we got warm enough in our damp sleeping bags to fall asleep, the guys would start playing a boom box with creepy children sounds outside the tent. So a lot of what you’re seeing on film, is directly following a collective groan, when we realized we had to pull our shoes back on and start acting again.

Sanchez : It was like theater in the woods, and we played the Blair Witch, so it was at certain times, you'd be like, "Alright, it's midnight, we have to go out there and run around or whatever," and each night we had a plan, so we would go out there and we would get into little groups and make noises, and make more noises, and do this, do that, and once we got what we needed, we were like, "Okay, we're good," and walked out of there at 2 AM after scaring [the actors].

Myrick : We laugh about kind of a famous line that Gregg gave the actors. He says something to the effect that, "Your safety is our primary concern, but your comfort is not."

Williams : Let's say the first day was a sandwich and a bag of chips for lunch, and the second day was maybe just the sandwich, the third day was maybe just the bag of chips, the fourth day maybe we didn't have a lunch. By the last couple of days, there was enough to sustain, but not a lot of food. So they decreased the amount of food we were eating, which we knew was going to happen, but it wasn't like... It wasn't like we didn't eat for days. Our safety was never at risk. The whole idea was to have us as uncomfortable as possible without putting us in danger.

Myrick : We wanted to maintain that as each day rolled out, they, as actors, wouldn't know anything more than what their characters would know at the time. When Josh or Mike asks a question of Heather on camera, it's a legitimate question.

Williams : The first night or two, nothing really happened, and then eventually they started to... You could kind of hear them walking around, breaking stuff, throwing rocks at trees. It was actually really cool because you never saw where they were. You knew it was them, but your job as an actor is to put the reality of it being those guys out of your mind, just focus in on the sound. It kind of created circumstances that were very easy for us to believe were creepy. But that said, after the third or fourth night or the fifth night, you're really exhausted, and I remember we would wake up and be like, "Guys, do you hear that?" and we'd be like, "Yeah," and "Ugh, do we have to get up and do this?"

Sanchez : I had a boombox with a cassette, and we had recorded Josh a few days earlier yelling all those lines. There was a take where somebody was upstairs with a boombox, and somebody was downstairs in the cellar, so I was out in the woods right next to the tent. Once I realized they were asleep, I hit play.

Myrick : We needed a moment where she finally, after Josh is gone, she finally realizes she fucked up. It was in the script where there's this confessional at some point where you just go off by yourself and say goodbye. You say goodbye to your family, apologize, it would be like if you were on a boat out in the middle of the Pacific, and you insisted on going a certain direction, and everyone said no, and there you are, now you're sinking, what would you say? And so we had that moment scripted pretty early on, but we allowed Heather to just take the camera and said, "Make sure you point it at yourself, as you're doing this sort of selfie monologue, but just say what you would say as your character to your family and friends, and this is the moment where you come to terms with what you've done." That's when Heather took the camera and went off and did her performance.

Myrick : They knew [how the ending was going to play out]. The house scene was probably the most traditionally shot segment of the movie, because logistically, it was just so complicated. Our first take of them approaching the house was genuine. When they emerged from the campsite and saw that house, they're seeing that house for the first time.

Williams: My direction for the last scene was "Mike will hear something tonight, and when you hear it, you're going to follow it all the way up, until Heather reaches you, and when Heather reaches you, you want to run all the way down." Now of course, I don't know it's a house, right, so I don't know what all the way up means, I don't know what all the way down means, I don't know what I'm going to hear. We had walkie talkies to radio to Ed Sanchez, and I said, "I don't really understand the last note," and he just said, "Listen, I promise you, you will understand it when it happens," and I said, "Ok," so I turned the radio off, went to sleep, and then I woke up and then the sound was Josh's voice on a boombox, so I had to follow Josh's voice, and I see the house, and I realize right in that moment what all the way up means.

Myrick: We had to map all of that out in advance, and work our way through each take, and ultimately cut it all together to make it look like it was one continuous take.

Before Sundance, the filmmakers made their own site that pretended the disappearance of the film's stars was real, becoming one of the first instances of viral marketing. Once Artisan Entertainment saw the brilliance of the marketing, they decided to redesign the site and keep up the act of the film's story being real.

Sanchez: The site went live in June of '98, which was before Sundance, and we built the site, pretending this was real and laid out a timeline and all these things, a little biography about Heather, Mike, and Josh, a timeline of the mythology of the case, and we had Heather's journal up there, just setting up the idea that we had been hired by Heather's mom to edit the footage, We weren't marketing it at all. It was just word of mouth, but when we got to Sundance, we had like 10,000 people on our mailing list, which was pretty big number for 1999, and so the site really helped us kind of get on the map.

Myrick: Artisan took our website conceit that this was sort of a real incident that took place in Maryland and ran with that. When we went to Cannes, they made up these "missing" flyers and had interns post them all around Cannes, and that made a big splash. So for a couple of weeks after the movie sort of hit the national scene, people thought the three actors had actually disappeared, and it wasn't until they were making talk show appearances and stuff that people realized it was just a movie. But they kept that going for a little while.