One of the most widely debated mass UFO sightings in history, the Phoenix Lights incident consisted of two distinct sighting events that took place on March 13th, 1997.
In both cases, witnesses described a distinctive V-shaped formation of bright, orb-like lights which moved in formation across the sky as though part of a single, large object.
First SightingThe first series of sightings occurred between approximately 7:30pm and 8:45pm on the evening of March 13th, 1997 when multiple witnesses described seeing a formation of lights in the sky moving across the state of Arizona in a southerly direction.
Witnesses included a former police officer (whose identity remains unknown) who reported "reddish-orange" lights that disappeared toward the south.
The phenomenon was witnessed by hundreds of other people over a succession of towns (including Paulden, Prescott Valley, Glendale and Scottsdale) as the lights continued to move across the region.
Tim and Bobbi Ley, who observed the lights with their family over Prescott Valley, believed that they were able to make out a large object, like a carpenter's square, into which the lights were set.
It moved extremely slowly and even passed a mere 150ft above them without making any noise.
They continued to watch as the object moved off over the Piestewa Peak Mountain range.?
Second SightingThe most widely reported event that day happened from around 10pm - 10:30pm when a similar V-shaped formation of lights was observed over the metropolitan area of Phoenix.
This time the phenomenon was witnessed by thousands of people and made local headline news.
Some witnesses claimed that the lights had been fixed to the underside of some sort of large craft, while others maintained that they had seen the lights gradually falling from the sky.
The incident went on to generate a great deal of debate and controversy in the years that followed.
Possible ExplanationsOfficially, the explanation for the events that happened that day was that the sightings had been a consequence of an Air National Guard pilot training program known as Operation Snowbird.
The sightings earlier in the evening were said to have been of a formation of A-10 Thunderbolt II aircraft returning to Davis-Monthan Air Force Base in Tucson.
The mass sighting over Pheonix, meanwhile, was dismissed as little more than illumination flares that had been deployed by other A-10 aircraft during a training exercise in southwest Arizona.
These explanations would go on to become a subject of major contention between believers and skeptics, with one side arguing that planes and flares could not have accounted for all of the sightings that day and the other maintaining that the entire incident has been satisfactorily explained.
Even today, many remain unconvinced one way or the other.