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. They were continuing work begun by British tunnellers months before. They secretly dug two large mineshafts under Hill 60 and The Caterpillar. Right along the British front were 17 other similar mines, all packed with explosives. At 3:10am 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 (18m) deep and 260 feet (79m) 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. As offical war historian Charles Bean wrote:
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]