"I was abducted by aliens twice 25 years ago," said this man, who withheld his name when he was photographed for "Phenomena," an upcoming book by Danish photographers Peter Helles Eriksen, Sara Galbiati and Tomas Salnaes Markussen. "The first time, (the aliens) put an implant behind my ear, and the second time they came back to remove the implant. I always hoped that if I would have an encounter with aliens, that they would be friendly. But these were not. They treated me like an animal."
A painting shows an alien at the International UFO Museum and Research Center, which is in Roswell, New Mexico. In 1947, an officer at the Roswell Army Air Field released a statement saying, "We have in our possession a flying saucer." The next day, the military said it was just a weather balloon -- but conspiracy theories have persisted for decades.
A giant lamp, shaped like a UFO, lights up in front of a bar in Rachel. For their book, Eriksen, Galbiati and Markussen visited various cities in Nevada, Arizona and New Mexico.
Lyle Michel holds a crystal pendulum during a group meeting in Las Vegas about UFO and alien experiences. "We thought maybe there would be like two people at this event, maximum. We thought this would be very small," Galbiati said. "But there were like 15 people there, so actually it was a big event. And people just told all kinds of stories. ... (It was) like we stepped into another world. A world we never knew of."
There are 27 radio telescopes that make up the Very Large Array, an observatory in the New Mexico desert.
Melinda Leslie is the director of "UFO Sighting Tours" in Sedona, Arizona. Several times a week, she arranges field trips in the red mountains outside of Sedona.
A churchgoer sits at Roswell's Washington Baptist Church. The pastor of the church is also the owner of Roswell's biggest UFO souvenir shop.
A man holds rocks in the middle of the Nevada desert near Area 51. He collects the rocks and sells them as souvenirs.
A UFO sculpture in Rachel.
Norio Hayakawa calls himself an "unorthodox ufologist and activist." He's had a lifelong fascination with UFOs, and he's the director of a group called the Civilian Intelligence Network.
A mural on the wall at the UFO Museum in Roswell.
John Lear, a retired airline captain and CIA pilot, takes a nap in his home on the outskirts of Las Vegas. He is a world-famous UFO researcher known within the community as "The Godfather of Conspiracy." He spends all his time going through material people send him from all over the world. "People send me different stuff like tips and stories and all kinds of information," he said. "I've probably been at my desk for eight to 12 hours every day the last 15 years."
A cat sits near the window of George Knapp's home in Las Vegas. Knapp is a TV reporter whose 1989 interview with Bob Lazar changed UFO mythology. Lazar told Knapp he worked at a secret underground lab near Area 51.
Jim Dilettoso is known in the UFO community as one of the leading analysts of potential UFO pictures and videos. Jim analyzed the video footage of the famous Phoenix Lights incident of 1997, and he determined that it couldn't have been anything manmade.
Footsteps are seen at North Main Street in Roswell. There are souvenir shops there selling UFO and alien merchandise.
Travis Walton said he was abducted by a UFO in 1975. He reappeared five days later.
Inside this suitcase are small fragments of metal found at the Roswell crash site from 1947. The suitcase belongs to Frank Kimbler, an assistant professor of Earth science at the New Mexico Military Institute.
Kimbler searches the crash site in his spare time.
This photo was taken at the crash site in the New Mexico desert.