IT WAS a photograph that spawned a multi-million-pound industry, bringing monster hunters from across the world flocking to Scotland.
The shot of a sinister head and elongated neck rising from the brooding waters of Loch Ness was all it took to start a global obsession with Nessie.
And 75 years since the mysterious shape was photographed, the search for the monster shows no sign of abating, with more than 1,000 people claiming to have caught a glimpse of the world's most elusive monster – despite the picture being revealed as a fake.
The photograph, which was claimed to have been taken by a London surgeon, Robert Wilson, and known as "Surgeon's photo", has also helped to bring in millions of pounds in "Loch Ness Monster" tourist trade.
The picture, taken on 19 April, 1934, was published in the Daily Mail two days later and triggered a public passion for "Nessie" that lives to this day. Cary Cooper, professor of psychology and health at Lancaster University, explained why he thought "Nessie" had captured people's imagination for so many years.
"In general, people's lives are incredibly mundane and predictable, and from that a desire to find something "inexplicable" – monsters, spaceships or aliens, runs through us," he said.
"Science says Nessie cannot exist, and even if she did they would have found her by now, but that only seems to fuel the flames for theories.
"The picture has been dismissed as a fake, but that has not stopped people wanting to believe that she is real – that she defies what the scientists tell us.
"If you add to people's natural leaning for a belief in the unexplained the slick marketing machine behind the monster, then you have a mystery that will never die."
References to a creature in Loch Ness date back to St Columba's biography in 565, but the myth only took hold in the modern era after reports of a strange object and then a series of inexplicable photographs appeared in the press during the 1930s. While the first piece of photographic evidence of the Loch Ness Monster was a picture snapped by Hugh Gray on 12 November, 1933, the "Surgeon's photo" of the following year remains the most memorable.
David Bremner, whose family owns the Loch Ness Centre and Exhibition Experience in Drumnadrochit, as well as the 3D Loch Ness Experience in Edinburgh, said: "It's one of the most iconic photos in Scotland, recognised all over the world. Although now is recognised as a hoax, it still shouts out "Scotland".
"People remain fascinated by the idea of the Loch Ness Monster, and in the intervening years we have had more than 1,000 sightings from people, including priests and police chiefs. You can't put a figure on the millions of pounds the photograph has brought in to Scotland."
Over the years, local rumours reinforced ancient Scottish myths about water creatures called "kelpies" . In the 1930s, talk of the monster reached fever pitch and Nessie-hunting took hold after a string of sightings.
Circus impresario Bertram Mills reportedly offered 20,000 to anyone who could capture the monster for his circus.
In 1933, a newspaper hired a big-game hunter, Marmaduke Wetherell, to track down the monster and he claimed to have uncovered its footprints by the banks of the loch. However, researchers from London's Natural History Museum declared that the tracks were fakes.
Mr Wetherell was so angry with the newspaper's coverage of the fake tracks that he set about ensuring his revenge.
Yet it was only in 1994 that the truth finally emerged – when Christian Spurling, 90, Mr Wetherell's stepson, confessed to his part in a plot involving both Mr Wilson and Mr Wetherell to fake the "Surgeon's photo" using a toy submarine fitted with a sea-serpent's head.
Darrel Patterson, of the Loch Ness Monster Exhibition Centre, said that picture remains one of their top-selling postcards.
"It's just so iconic," he added.
A LOCH WITH A DARK SECRET
• LOCH Ness is 23 miles long and 1 mile wide.
• The deepest spot is about 754 feet in the basin just south west of Urquhart Castle.
• John Murray carried out the first bathymetrical survey of Loch Ness in 1901.
• The BBC's Royal Correspondent Nicholas Witchell wrote the first edition of his book, Loch Ness Story, while living in a hut on a bend in the road just north of Urquhart Castle.
• The Official Loch Ness Exhibition opened in 1980 and the first day's takings were 80.80.
• The centre now receives more than 300,000 visitors each year.
• In 1969 a model monster was used for the film The Private Life Of Sherlock Holmes.
It sank into the loch while being towed by the submarine Pisces.
• In 1982 Dr Maurice Burton proposed in an article for New Scientist magazine that supposed sightings of Nessie could actually be fermenting logs of Scots pine rising to the surface of the loch's cold waters.