The mountaintop and what occurs there has played a central role in the mythologies of civilizations gone by, and these stories speak volumes about how the people telling them interpreted the world around them. The Ancient Greeks had Olympus, which was believed to host a pantheon populated by immortals. Jews and Christians have Mount Sinai, which they believe Moses ascended to receive the Ten Commandments. And Phoenix, Arizona has the Sierra Estrella—a mountain range that many Phoenicians believe is presided over by UFOs.

The story begins on March 13, 1997, when thousands of Arizonans from all across the state reported seeing strange lights in sky. It remains one of the largest UFO sightings ever, but the details of the Phoenix Lights story ultimately depends on who is telling it—some contend that it was actually a composite of two separate events occurring simultaneously over Arizona, and there is little consensus as to whether these lights were extraterrestrial in origin.

As a longtime resident of Phoenix and UFO agnostic, I've heard the story of the Phoenix Lights retold countless times, each retelling rife with contradictions and inconsistencies. So, tired of the hearsay, I decided to visit the International UFO Congress to see if I could discover the truth about one of history's most infamous UFO sightings.  

Image: Daniel Oberhaus/Motherboard

Each year, hundreds of people gather in the foothills of the McDowell Mountains outside of Phoenix, Arizona for the International UFO Congress. Presided over by Alejandro Rojas, an Arizona real-estate agent and the guy behind the online UFO hub OpenMinds , the congress has been going strong since it first started in 1991. The highlight of this year's congress was a panel of Phoenix Lights eyewitnesses who wanted to share new developments in the Phoenix Lights story on its 20th anniversary.

Among these witnesses was Lynne Kitei, a Phoenix area physician and perhaps the closest that anyone could come to being an expert on what occurred that March evening 20 years ago. She has written a book and produced a full-length documentary on the subject and also maintains the Phoenix Lights Network, a hub for people to meet up and discuss the phenomenon.

"I put my medical career on hold for four years afterwards to investigate the Phoenix lights and have dedicated my life for 20 years just to get information out there," Kitei told me at the congress. "Let me tell you, a day does not pass by that I don't get an email from somebody that saw a similar phenomenon."

The phenomenon in question began at approximately 7pm on the night of March 13, 1997 when people in northwestern Arizona reported seeing a massive craft pass overhead. According to the National UFO Reporting Center, one of the few organizations that bothered to keep an official record of Phoenix lights sightings, the first call it received on its UFO Hotline that night came from a retired police officer in Paulden, Arizona, a small town about 2 hours north of Phoenix. The man reported seeing a cluster of red-orange lights arranged in a V-formation.

According to the write up of the event, after the initial report, calls began "pouring into the Hotline" from locations south of Paulden, indicating that the craft was heading in a southeasterly direction. While some of the specifics from these reports were slightly different, as USA Today would report a few months after the fact, the reports were united by several key observations, namely: the craft was enormous (witnesses described it as a mile wide), it made no sound, and moved slowly over Arizona, often times stopping to hover in a single location.

Lynne Kitei signing books at the UFO Congress. Image: Daniel Oberhaus/Motherboard

According to USA Today, the craft traversed Arizona in 106 minutes based on witness reports. Interestingly, however, a second incident that same night occurred around 10pm Arizona time, about an hour after the last reports of the large V-shaped craft had come in from the southern portion of the state. This event, which is the subject of the few Phoenix lights photos that exist, consisted of an arc of blinking orbs that moved slowly over Phoenix before promptly disappearing as soon as they reached the Estrella mountain range southwest of the city.  

One of the most remarkable things about the Phoenix lights is how many people witnessed them. The reason for this, Kitei told me, was that many Arizonans were outside stargazing that night to observe Hale-Bopp, an unusually bright comet that was approaching its closest pass to the Sun on April 1. Interestingly, Hale-Bopp was also believed to have an extraterrestrial craft in tow by members of the Heaven's Gate UFO cult in California, which led 39 members to commit suicide just 11 days after the Phoenix lights sighting in Arizona, although the two incidents are unrelated.

In any case, despite the number of people who reported witnessing the lights pass overhead, there was no official acknowledgement of the event and no media coverage until USA Today picked up the story that June.

2017 International UFO Congress. Image: Daniel Oberhaus/Motherboard

The USA Today report brought international attention to the Phoenix lights phenomenon, and people began demanding answers. The most obvious explanation for the lights was that they were the result of military exercises being conducted in the area, which isn't so farfetched considering that Phoenix has two air force bases near the city. Indeed, subsequent reports in local newspapers such as The Arizona Republic and Phoenix New Times began stacking up the evidence that the Phoenix lights were just a military training exercise.

Read More: This Neuroscientist Wants To Know Why People Who See UFOs Feel So Good

According to the New Times, three months after the lights, a local television reporter filmed a flare drop by military planes at an Air Force gunnery range south of Phoenix, and the resulting footage "looked remarkably like the 10pm lights of March 13." Moreover, days after that report the Tucson Weekly reported that the Maryland Air National Guard had been in Arizona for winter training and had dropped flares from a few A-10 fighter planes at the gunnery behind the Estrella mountain range. While this may have accounted for the second event of the night, a spokesperson for the National Guard had said that the planes never went north of Phoenix, so the initial sightings remained unaccounted for.

"We know that that same night there was a whole bank of illumination flares put up by the Air Force over the Barry Goldwater test range," Jim Mann, director of the Arizona Mutual UFO Network, told me. "A lot of people say the Phoenix lights aren't real, that they're just military flares, but a lot of research has led us to realize that the Phoenix lights were just a small portion of this huge UFO event."

Jim Mann, director of the Arizona Mutual UFO Network. Image: Daniel Oberhaus/Motherboard

Indeed, many shared Mann's skepticism that the Phoenix lights were reducible to military flares. Aside from the reports that came from the far north of the Arizona, independent analyses of footage of the Phoenix lights were performed by videographers working at a special effects company in Phoenix, as well as Paul Scowen, a professor of astronomy at Arizona State University who also independently analyzed video footage of the lights and found that they disappeared as soon as they hit the Estrella mountain range.

Still, the incident was dismissed as fantasy. Shortly after the front page USA Today story that brought international attention to the event, the incumbent governor of Arizona, Fife Symington, held a press conference during which he claimed to have "found who was responsible" for the lights. During the conference, Symington trotted out someone dressed in an alien costume with their hands cuffed.

"They made a mockery of the whole thing and it was really disconcerting," said Kitei. "They were trying to make a joke out of it, but people were taking this seriously. They wanted to know what these things were and who was doing it."

Although Symington made light of the sightings at the time, on the 10th anniversary of the event, he claimed that he had in fact witnessed the phenomenon in 1997.

"I'm a pilot and I know just about every machine that flies," Symington said. "It was bigger than anything that I've ever seen. Other people saw it, responsible people. I don't know why people would ridicule it."

Ultimately, the story of the Phoenix lights blurs the line between delusion and reality, so it seems these UFO-observers must find equilibrium in a profound and righteous paranoia. In some ways, it is a matter of indifference whether it turned out the military behind the lights or it was the work of extraterrestrial beings—either way it is confirmation of a vast web of either military or extraterrestrial power that is hidden from sight, as well as the lies and omissions it requires to stay hidden. But despite all the ufologists who want to believe that the Phoenix lights were other worldly, many remain skeptical about the origin of the craft.

"I think it's a little premature to say it was an alien ship," said Mann. "This is a mystery. Something happened, we don't know what it was, we just know that it happened."

When the astronomer Josef Allen Hynek was enlisted by the US Air Force to conduct a number of studies on UFOs in the 1940s and 50s, he found that from the hundreds of reported sightings, only a couple of dozen seemed to lack a scientific explanation. This is what makes the Phoenix lights such a unique UFO case—to this day, it remains an unresolved phenomenon, one that was witnessed by hundreds, if not thousands, of people, many of whom had never taken UFOs seriously before that spring night in 1997.

In any case, when it comes to the Phoenix lights, conspiracy is to be found at every turn. Indeed, after my visit to the UFO Congress, the only thing I knew for sure was that the stories that create and define the UFO phenomenon were united by one detail: they are told by people who are inclined to look up.