The men were part of a larger group of 34 who were buried alive when an Allied shell exploded above the tunnel in 1918 causing it to cave in.

Thirteen bodies were recovered from the underground shelter but the remaining men had to be left under a mountain of mud as it was too dangerous to retrieve them.

Nearly a century later French archaeologists stumbled upon the mass grave on the former Western Front during excavation work for a road building project.

Many of the skeletal remains were found in the same positions the men had been in at the time of the collapse, prompting experts to liken the scene to Pompeii....