From 1914 to 1917 the German pioneers consolidated the position. The hill was pierced from all sides by subterranean timber-propped galleries, some leading to immense and comfortable shelters, others to numerous invisible observation-posts, so placed as to command an extensive view in all directions. A large number of camouflaged heavy guns were posted on the slopes of the hill, the neighbouring observation-posts ensuring great accuracy of fire. Trenches had been dug all about, in the chalky soil. At the foot of the slopes, two first-lines completely surrounded the hill, and two similar lines ran round half-way up. Communication-trenches zig-zagged transversely, connecting the various lines of main trenches, while the intervening empty spaces were covered with deep entanglements of barbed wire and _chevaux-de-frise_. Lines of barbed wire protected the winding communicating trenches. At the corners, at regular intervals, concrete observation and special posts, all strongly fortified, were built for the machine-gunners and sharp-shooters. [Illustration: GERMAN OBSERVATION-POST ON MONT-ST.-QUENTIN (IN THE CHÂTEAU PARK). _Péronne and Maisonnette Hill are in the background._] [Illustration: SPY-HOLE OF THE OBSERVATION-POST.] The village itself was powerfully fortified. An intricate system of trenches entirely covered the place, the castle forming the main strong-point. A maze of communication trenches and entrenchments ran throughout the park. A concrete observation-post on the terrace, near the enclosing wall, hidden among the lime-trees, commanded a view of the whole battlefield north and south of the Valley of the Somme. A subterranean shelter beneath this observation-post connected the defences of the castle with those in the cellars of the village houses. [Illustration: MONT-ST.-QUENTIN. RUINED HOUSES.] These powerful entrenchments have almost completely disappeared. Before evacuating the position in March, 1917, the Germans mined the defence-works of the hill, blocking up the entrance to the underground passages. They also set fire to the timber props which supported the roof and walls of the galleries and shelters; an immense fire was thus lighted inside the hill, which, for several days, had the appearance of a volcano in eruption. [Illustration: MONT-ST.-QUENTIN. GERMAN DEFENCES.]