Battle of Messines 7 to 14 June 1917
The Battle of Messines was an important attack before the major British offensive for 1917, the Third Battle of Ypres.
At the time,the Germans held Messines Ridge. This position formed a salient (bulge) into the British line on the southern flank of the planned Ypres attack. It also gave German artillery observers a good view of the ground west of Ypres, where the British planned to gather their forces for the attack. The ridge had to be captured before the Ypres offensive could start.
The plan was for 3 British corps to attack German positions on Messines Ridge, including II Anzac Corps at the southern-most point.
The battle commenced a few minutes after 3 am on 7 June. It started with the detonation of 19 mines under the German trenches, which tunnellers had secretly dug over the previous year. The explosions created enormous craters, some of which are still visible today.
The huge series of explosions obliterated the German front line and left the survivors stunned.
At first, the British advance was unopposed over much of the front. British forces easily captured the ridge and thousands of prisoners, and German counterattacks failed.
Over the next 2 weeks, further British advances were made. About 26,000 men were killed, wounded or captured on each side. The Australians were withdrawn in July, fought at Ypres from September, and then returned to garrison the Messines trenches through the winter of 1917 to 1918.
Hill 60 mine from 9 November 1916 to 7 June 1917
The opening of the Battle of Messines was at that time the biggest man-made explosion in history.
At Hill 60, at the northern extremity of the line, the 1st Australian Tunnelling Company had been at work since November 1916. The Australian tunnellers were continuing work begun by British months before. They secretly dug 2 large mineshafts under Hill 60 and the Caterpillar (Kofferberg to the Germans).
Right along the British front were 17 other similar mines, all packed with explosives.
At 3:10 am on 7 June 1917, British forces simultaneously blew up 19 mines as the opening move in the Messines attack. The Hill 60 mine created a crater 60 feet (18 m) deep and 260 feet (79 m) wide. The German front-line troops were overwhelmed.
After the explosions, and preceded by a creeping artillery barrage, the Australian, New Zealand and British troops advanced to find a shattered enemy.
Everywhere, after firing a few scattered shots the Germans surrendered as the troops approached. Men went along the trenches bombing the shelters, whose occupants then came out, some of them cringing like beaten animals. They 'made many fruitless attempts to embrace us,' reported Lieutenant Garrard of the 40th. 'I have never seen men so demoralised'.
[Charles Bean, The AIF in France 1917, Volume IV, The Official History of Australia in the War of 1914–1918, Sydney, 1941, p.595]