UFO watchers believe that in 1947 a flying saucer with aliens on board landed outside the New Mexico town of Roswell and that an elaborate cover-up by the authorities followed. The BBC’s Kevin Connolly went to Roswell in pursuit of the truth about the Roswell incident.
There is a lunar quality to the landscape of New Mexico which seems somehow appropriate for a state which is our portal to the heavens.
It is here on a dried-up lake bed high above sea level that the radio telescopes of the US government’s Very Large Array (VLA) send signals to the outer edges of our expanding universe, chasing the very moment of the Big Bang through the trackless void of time and space.
And of course it is also here - perhaps - that 62 years ago a flying-saucer crashed to earth on a ranch outside the town of Roswell, killing its alien crew and prompting one of the most elaborate and protracted cover-ups in history.
The power of that possibility and the darkness of the nights here so far from the light pollution of the big cities are what draw scientists and curious tourists alike to this entrancing place.
And it is what motivates watchers of the skies to keep, well, watching the skies, obviously.
If UFO true-believers are right, then nothing much that has happened on our tiny, fragile planet in the years since that stormy summer’s night really matters very much.
What, after all, would Watergate, or Vietnam or Iraq amount to if we could establish that the US government knew for sure that we are not alone in the universe?
Most of the big questions about alien life and UFOs can be traced back to Roswell - not least the issue of how life-forms from another civilisation have such an uncanny sense of when the tourist industry in a small US town could use a shot in the arm.
Are we really alone in the heavens, for example, and if we are not, do the civilisations with which we share the heavens mean us any harm?
Is it just a coincidence that aliens have never managed to find an earth-dweller who knows how to operate his own camera properly?
And why, if you have journeyed light years across the unknowable vastness of the heavens, would you confine yourself to a fleeting and ambiguous appearance before a handful of New Mexican ranchers?
Why not go the extra mile and find a research institute of some kind - unless our visitors have a sense of humour, of course.
But we are getting ahead of ourselves.
Let us return to that stormy summer New Mexican night in 1947 when the story of the UFO landing first broke.
It was a world of tension and uncertainty.
The United States had detonated the first atom bombs - they were developed just up the road at Los Alamos, New Mexico - and was uneasily aware that the Soviet Union, its increasingly hostile former ally, had nuclear ambitions of its own. The Cold War was just beginning.
Roswell was in those days the home base of the 509th Bombardment Group of the US Eighth Army Air Force.
Most of the boys in the 509th were combat veterans and when they were tasked to investigate reports of some kind of landing on a ranch a short distance away it seems reasonable to assume they were not too excited at first. That soon changed.
When they got the material back to base, they quickly concluded they were onto something historic.
Their first press release talked of the recovery of a flying saucer - it was only when the suits descended from Washington that the tone of the official communiques changed.
The base intelligence officer who was tasked with taking the wreckage to another base reports leaving it in an office there and returning a few minutes later to find that the space debris he had brought had been replaced with parts of a weather balloon.
The fix was in.
The truth about Roswell?