A road sign near Rachel, Nevada in 2002 (Photo: AP)
The U.S. Central Intelligence Agency (CIA) has acknowledged that Area 51 existed, and revealed exactly where it was located.
According to a newly declassified 1992 internal CIA document, the location in Nevada near Groom Lake was a secret U.S. test site for the U-2 spy plane programme.
The same document makes reference to the increase in UFO sightings and the rumours that surround the site.
But it also offers an explanation for those sightings: according to the report, the strange aircraft that pilots and others spotted in the area were actually U-2 planes, flying at a higher altitude than other aircraft at the time could reach.
All the UFO-sighting letters led to the creation of the Air Force's "Operation BLUE BOOK", which collected "all reports of UFO sightings."
Any amateur Mulders or Scullys out there might be interested in this section of the document, explaining how BLUE BOOK investigators checked reported UFO sightings against flight logs to see whether the sightings were actually government aircraft:
"This enabled the investigators to eliminate the majority of the UFO reports, although they could not reveal to the letter writers the true cause of the UFO sightings. U-2 and later OXCART flights accounted for more than one-half of all UFO reports during the late 1950s and most of the 1960s." (Emphases added).
You can almost hear the UFO community now: "more than one-half"? What about the rest of the sightings?
While it may not offer any clarity on the existence of extraterrestrials, the report does go into a lot of detail about Area 51 itself and the work that took place there.
The nature of that work certainly explains why details about the site haven't come out until now.
"The U-2 was absolutely top secret. They had to hide everything about it," British defence journalist and author Chris Popcock told the BBC.
You can read the full report below: