Tunnel and dugout excavations carried out by the Association for Battlefield Archaeology and Conservation (ABAC) in the Ypres Salient are shown in these three photographs. The flooded conditions ensure remarkable preservation of timber and other organic materials underground. Under the direction of local mining engineer Johan Vandewalle and historian Peter Barton, for over 15 years ABAC has built up considerable expertise in this potentially extremely hazardous activity and has a detailed database of over 350 First World War underground structures. Excavations are now closely controlled by the authorities.

Bunks in the main gallery of Martha House Dugout, 1996. The wire netting shows the impressions of sleeping British soldiers, although the dugout was still under construction when the area was recaptured by the Germans in April 1918. (Copyright Johan Vandewalle ABAC).