Somewhere in France there lies buried a small bronze statuette of an owl in flight. Whoever finds it is promised not just the prize of the original sculpture made of gold and silver, but the kudos of having won the world's longest-running treasure-hunt, reports BBC News.
Sur La Trace de La Chouette d'Or [On the trail of the golden owl] was an illustrated book first published in 1993.
At the time there was a vogue for such armchair treasure hunts inspired by the UK's best-selling Masquerade, in which artist Kit Williams laid out a series of complex visual clues for finding a golden hare.
But while all the other riddles, including Masquerade, were eventually solved, the French owl is still out there. And, amazingly, people are still looking.
A quarter of a century on, thousands of so-called chouetteurs continue to pore over the book's 11 enigmas, which can be downloaded free over the internet. They exchange theories in chat forums and meet at annual get-togethers.
There is even an association set up to defend their interests in court.
"I have been looking since August 1993," says Pierre Blouch, a founding member of the A2CO association.
"I remember at the time thinking we had better get a move on, because we were starting three months after the book was published. Little did we realise."
Like many fellow owlers, Mr Blouch has had his pet theories, and at one point could be seen digging up various spots around the city of Bourges.
A retired engineer, he now spends his time sifting through the online literature and hoping for new inspiration.
Deciphering the clues appears to require a combination of scientific knowledge, imagination and a head for codes.
The 11 enigmas are supposed to lead to a town in France, and then there is a hidden 12th enigma made up of left-over bits of the 11 that pinpoints the exact spot.