Decipher Breton rock riddle and win €2,000

People across Asia, Chile, Russia, the US, and much of Europe contacted Plougastel mairie in Finistère, Brittany, with theories on deciphering the hundred or so characters and pictograms.

One part dates to the 1920s and another to 1786.

The rock can be reached only at low tide. It has been called the mystère Champollion, after the Frenchman who decoded the Rosetta Stone.

Véronique Martin, from the mairie, said: “I thought it would only be of interest in France but it has gone worldwide.

Whoever gives the best translation wins a €2,000 prize, with a jury of academics ready to rule on replies.”