All the officers of the brigade who were to participate in the "Big Push" were invited over to Brigade Headquarters that evening by the Brigadier General. We were shown some aerial photographs of the German trenches that had been very recently taken, and given more minute details of the attack, with the information that the "Zero Hour" would be 5.30 A.M., and that the first wave was to go "over the top" at one minute past "Zero Hour." The reason that the first wave was to go over at one minute past "Zero Hour" was to give time to the barrage to play three minutes on the German front line. We thus had two minutes to work under the barrage before it lifted to the next objective. As it lifted, we would make a rush for our first objective and follow our barrage to within 50 yards. The "Zero Hour" was to be kept secret. The General then gave us a history of Vimy Ridge, again telling us he was certain, on account of the wonderful artillery support we would have, that we would gain all our objectives. How true his words were is now history. Between the city of Arras, held by the French and British, and the city of Lens, held by the Germans, was Vimy Ridge which stretched north, west and southwest in front of the village of Vimy. Since 1914, the Germans had held it, resisting all Allied assaults. Its strategical importance was fully recognized by both the Allies and the Germans. Every artificial means had been taken to increase its natural strength, the best scientific devices of fortifications had been made use of by the Germans, and for two years it had defied all attacks. The French vainly attacked it all through the month of December, 1914, and January, 1915. General Foch in May, 1915, delivered several attacks known as the Battle of Souchez. He gained a little ground on the lower slopes, but failed to weaken to any extent the Main Ridge. In September, 1915, while the British were making an attack around and near Loos, the French under General Foch once more attacked the Ridge. Again they failed. As long as the Germans retained Vimy Ridge, their line was secure in this quarter, so its retention allowed them to contemplate with a certain degree of equanimity withdrawals of troops from the line. On either side of the Ridge, it was flanked with Lens on the north, and Arras on the south--both cities under distant artillery fire.