The event, which came to be known as the Roswell Incident, had its origins in a press release issued July 8, 1947 by the 509 Bomb Group based at the Roswell airfield that army personnel had recovered a "flying disk" which had crashed on a nearby ranch.
Although the command of the Eighth Air Force issued a retraction that same day, stating that in fact the recovered craft had been a weather balloon, intense media interest and public speculation prompted the authorities to hold a subsequent press conference at which the remains of a weather balloon were displayed that seemed to confirm the Air Force's account.
The incident was largely forgotten for some 30 years until 1978, when a prominent UFO researcher, Stanton Friedman, interviewed one of the participants in the recovery effort, one Major Jesse Marcel, who claimed that an alien spacecraft had indeed been recovered at the Roswell site.
In an interview, he recalled that material found at the alleged crash site by Roswell's sheriff and turned over to him, as the commanding intelligence officer at the Roswell Air Force base, was highly unusual.
"This material did not burn," he said, "it weighed practically nothing, it was thinner than the foil in a cigarette pack, and it didn't bend," he said.
This time the story did not fade, and in an atmosphere of widespread public distrust of the government in the 1970s following the Vietnam War and Watergate it blossomed into a cultural phenomenon, attended by myriad other sightings and rumors of secret autopsies on alien bodies.
In response to the public outcry, the government directed the Air Force to conduct an internal inquiry into the 1947 events, and in 1995 the Office of the Secretary of the Air Force issued a report that concluded the recovered debris was part of a secret testing program called Project Mogul.
A subsequent report released in 1997 maintained that the so-called alien corpses reported by eyewitnesses were in all likelihood simulation dummies used by the Air Force to test high-altitude falls.
Still, the skepticism of many was not assuaged, and to this day the Roswell Incident is regarded by many as the most important event in the history of UFO sightings.
At the 60th anniversary celebrations, which begin Thursday and continue through Sunday, Jesse Marcel's son, also named Jesse, will be a featured speaker when he presents his new book on the facts of the case.
"The discovery of a crashed flying saucer at Roswell is one of the most important events in UFO history," he wrote in the forward to his book.
Nevertheless, the Roswell Incident was not officially the first sighting of a UFO. That distinction goes to a man by the name of Kenneth Arnold from Washington State, who claimed to have observed nine mysterious flying objects June 24, 1947 that moved with incredible speed near the Mt. Rainier volcano before disappearing.