From the Beeb: France reveals British WWI cave camp.

France has reopened a labyrinth of medieval quarries under the northern town of Arras which the British army converted into an underground hideout for 24,000 soldiers during World War I. [continue]

• Inside the amazing cave city that housed 25,000 Allied troops under German noses in WWI – Daily Mail
• Tunnellers in Arras – mil.nz