This military hospital from World War I has remained almost untouched for the better part of a century.
Concealed within a limestone quarry in northern France, the facility still has a few of its Great War era stretchers and trolleys in place, as well as graffiti and carvings made by wounded soldiers during their convalescence.
Stored munitions - now dangerously unstable because of their great age – can still be found in some of the tunnels.
The precise location of the hospital, called Carrière Suzanne, is being kept secret until the explosives can be made safe and the tunnels can be restored to a condition suitable for visitors, but urban explorer Marc Askat worked out where the hospital was by reading old diaries and has made a photographic record of the site as it is today.
“I was looking for World War I remains, in particular sites protected by the shelter of the quarries,” Marc said.
“I was hoping to find places that haven't been damaged by people or the elements.
“One day, I found an abandoned underground network that was used by the British and French soldiers as an underground hospital during World War I, the ‘Carrière Suzanne’.
“People from the village next to the quarry were secretly working to restore the place.
“As it is very dangerous to visit and not yet fully protected from vandalism, the exact location remains secret for the moment.”
Marc – two of whose relatives were killed at the Battle of Verdun - believes sites like this are vital in preserving our living history.
“Underground, France is full of historical material,” he said.
“But this place is the only one where so many remains are still in the same place in a breathtaking state of preservation.
“This includes hospital beds, sculptures, ammunition and the graves of the dead.
“We can't let our history slowly decay over time. Instead we should all be able to discover this part of our past.”