the germans began Process_start systematic fortification of the area , according to a directive from erich von falkenhayn the german army chief of staff , to fortify the western front so that a small number of infantry could defend Defending the front indefinitely and later in the year began Process_start work on second and third defensive positions but in the somme area , the defences north of the unk were improved Cause_to_make_progress first and by july 1916 the first position defences around mametz were extensive but the second position was a shallow trench and the third position had only been marked Recording out .

operation `` hurricane '' was a 24-hour bombing Attack operation to `` demonstrate to the enemy in germany generally the overwhelming superiority of the allied air forces in this theatre '' ( in the directive to harris aco raf bomber command ) and `` cause mass panic and in the ruhr , disrupt frontline communications and demonstrate the futility of resistance '' ( in the words of the official raf history ) .