More than 2,000 perfectly preserved inscriptions were found on the walls of an underground cave in Naours , France . They were left for posterity by young men facing the horror of trench warfare some 25 miles away at the Somme . Experts believe the bored young soldiers used their spare time to visit the caves , which are well known locally . Only weeks later they were sent to the Somme battlefields , where more than a million men were killed or injured .
More than 2,000 perfectly preserved inscriptions were found on the walls of an underground cave in Naours , France . They were left for posterity by young men facing the horror of trench warfare a few dozen miles away at the Somme . Experts believe the bored young soldiers used their spare time to visit the caves , which are well known locally . Only weeks later they were sent to the Somme battlefields , where more than a million men were killed or injured .