What happened at Messines Ridge in Belgium in June 1917?

In June 1917, the Battle of Messines served as a masterclass in military engineering and meticulous planning. To secure the Messines Ridge—a position held by German forces since 1914—British forces under General Sir Herbert Plumer spent a year tunneling beneath the German lines.1

On June 7, 1917, the operation culminated in the detonation of nineteen mines containing approximately one million pounds of high explosives. This massive engineering feat created a "virtual earthquake" that killed up to 10,000 German soldiers instantly and left craters as deep as 45 feet. The explosion is considered the largest controlled blast in warfare prior to the development of the atomic bomb.1

Following the blasts, a "creeping barrage" from 2,000 guns protected advancing infantry, leading to a decisive British victory. This operation successfully cleared the ridge, providing a strategic advantage for the subsequent Battle of Passchendaele.1