简介：BeneaththeSommebattlefieldliesoneofthegreatsecretsoftheFirstWorldWar,arecently-discoverednetworkofdeeptunnelsthoughttoextendoverseveralkilometres.Thislostundergroundbattlefield,centredonthesmallFrenchvillageofLaBoisselleinPicardy,wasconstructedlargelybyBritishtroopsbetween1914and1916.Over120mendiedhereinongoingattemptstounderminethenearbyGermanlinesandthesegalleriesstillserveasatombformanyofthosemen.ThisdocumentaryfollowshistorianPeterBartonandateamofarchaeologistsastheybecomethefirstpeopleinnearlyahundredyearstoenterthishidden,andstilldangerous,labyrinth. Militaryminesweretheoriginalweaponsofshockandawe-withnowheretohidefromamineexplosion,thesehugeexplosivechargescoulddestroyaheavily-fortifiedtrenchinaninstant.InordertogetundertheGermanlinestoplanttheirmines,Britishtunnellershadtoplayaterrifyinggameofsubterraneancatandmouse-constantlylisteningoutforenemydiggingandtryingtointercepttheGermantunnelswithoutbeingdetected.Tolosethisgameprobablymeantdeath. Aswelluncoveringthegrimrealityofthisstrangeundergroundwar,Peterdiscoversthestoryofthemenwhoservedhere,includingthetunnellingcompanies'specialmilitaryunitsmadeupofordinarycivilliansewerworkersandminers.HerevealstheirtopsecretmissionthatlaunchedtheBattleoftheSomme'sfirstdayanddiscoverswhyBritishhighcommandfailedtocapitaliseonacrucialtacticaladvantagetheyhadbeengivenbythetunnellers.…