If a soldier from Mars had come to Earth at any time from October, 1914, to October, 1918, and had been shown on a flat map the fronts of the two adversaries, he would have said that the obvious strategic point of a single offensive would be between the Meuse River and the Argonne Forest. This would be a blow against the enemy's lines of communication: a blow equivalent to turning his flank. If the soldier from Mars had been shown a relief map, he would have changed his mind, and he would have perfectly understood, as a soldier, why all the offensives had been in the north, from Champagne to Flanders, where breaking through the main line of defenses would bring the aggressor to better ground for his decisive movement in the open. He would also have understood why the front from the Argonne to the Swiss border had been tranquil since the abortive effort of the Germans at Verdun. When Ludendorff undertook his great offensive of March, 1918, he did not repeat Falkenhayn's error, but turned to the north, where the Allies had made their attacks. In that Lorraine-Alsatian stalemate to the south, with the Vosges mountains and interlocking hills from Switzerland to the forts of Metz as the stronghold of the Germans, and the forts of Verdun, Toul, Epinal, and Belfort as the strongholds of the French, the odds were apparently too much against an offensive by either side to warrant serious consideration. Yet a watch was kept. Over the French mind was always the shadow of a possible German offensive toward Belfort; and, when the sector which our young army was to hold in Alsace and Lorraine had been first discussed in July, 1917, the French excluded the defense of a portion of the front opposite Belfort, with the polite explanation that they preferred to hold that themselves. But the Germans never did more than make the feint of an offensive in the south, which Ludendorff used in the winter of 1918 to draw off French troops and guns from the north: for the army with the numbers and the initiative of offense can always force the defense to waste movements to meet threats of attack. This was another advantage which the Allies could now use in keeping Ludendorff in doubt as to where our real blows were to be struck. The heights of the Saint-Mihiel salient, which look directly across the plain of the Woëvre to the fortress of Metz, may be said roughly to have formed the left flank of the Lorraine-Alsatian stalemate. They continue onward in the hills which are crowned by the forts of Verdun, and then across the Meuse River for a distance of twenty miles through the bastion of the Argonne Forest, where they gradually break into the more rolling country of Champagne. The Meuse winds past Saint-Mihiel and through the town of Verdun, and then, in its devious course, swings gradually to the northwest until, at Sedan, it turns full westward.