 On 7 June 1917, along with two British corps, the II Anzac Corps, consisting of the Australian 3rd Division, the British 25th Division and the New Zealand Division, with the Australian 4th Division attached, launched an operation in the Flanders region of southern Belgium, near Messines The objective was to eliminate a salient that had developed in the line south of Ypres, enclosing the Wytschaete–Messines ridge and thus providing the Germans with good observation and fields of fire that could threaten the major offensive that the British planned to launch around Ypres later in the year.The attack commenced with the detonation of of explosives that had been placed underneath the Messines ridge in 19 separate tunnels, completely destroying the German trenches.Following the explosions, the Allied advance was virtually unopposed as the Germans were too stunned and demoralised to put up much resistance.