One day I had tea with an Army commander who has done great things since then, and he showed me a series of photographs--the most interesting I have ever seen, which were taken the day before my visit, by our airmen, over the German lines. For seventeen and a half miles back, the enemy, with infinite care and patience, had constructed trenches, 'and,' said the Commander, 'every time we destroy his front line trench he constructs another one in the rear.' 'But,' I cried, 'if this kind of thing goes on, and unless the unexpected happens, the war must surely continue indefinitely.' His only reply was, 'Is it not always the unexpected that happens in war?' I was back again in Picardy in the summer of 1917, and the unexpected had happened. The whole of the seventeen and a half miles of trenches were in the hands of the British! The enemy had retired to the much advertised 'Hindenburg Line,' and leaving nothing to chance, was tirelessly, ceaselessly massing and training his men, getting together huge reserves of munitions, husbanding his resources in every possible way, and preparing, always preparing day and night for his next great move. Meanwhile, Italy's defences had to be strengthened by troops we could ill-afford to spare from our Western front, and Russia, in loyalty to whom we first entered the war, failed us altogether, German intrigue being the underlying cause in each case. In his great advance in March and April 1918 he did not achieve all he set out to do by any means, but his gains were enormous. It makes one sad to think of the territory we had temporarily to relinquish to the Hun in Picardy, even though the country itself was not of any intrinsic value. The land is desolate, and the enemy ruined every village and hamlet, every farm and cottage, before his retreat. Ninety-three Red Triangle centres--huts, marquees, cellars, dug-outs, and 'strafed' houses had to be abandoned in Picardy alone--most of them destroyed before they fell into the hands of the Germans.