Lapped by the waves of the Atlantic and visible at only low tide, a mysterious rock inscription believed to be centuries old and so far undeciphered lurks outside a French village in Brittany.
The town hall in Plougastel-Daoulas in the Finistere region of Brittany in northwest France is now offering a €2,000 reward for anyone who can decrypt the sequence of letters and symbol.
Could the small boulder have been used for a love letter whose secret has remained untouched for centuries, or a proud note left by an eighteenth-century fort-builder? Or something even more mysterious?
Locally, the rock is sometimes compared to the Rosetta Stone, the great ancient Egyptian stele now in the British Museum whose inscription was partly deciphered by the French Egyptologist Jean-Francois Champollion.
The authorities in Plougastel-Daoulas hope that their competition will shed light on the enigmatic piece of history. 
“This inscription is a mystery and it is for this that we are launching the appeal,” said Veronique Martin, who is spearheading the search for a code-cracker.
The rock, which is around the size of a person, is accessed via a path from the hamlet of Illien ar Gwenn just to the…