Tanks were used in battle for the first time

At dawn on 15 September 1916, during the Battle of Flers-Courcelette on the Somme, the British sent an entirely new machine into combat: the tank. Conceived to cross trenches and crush barbed wire while shrugging off machine-gun fire, the Mark I weighed about 28 tons and carried a crew of six.

The debut was as ragged as it was historic. Forty-nine tanks were earmarked, but only 32 reached the start line, and just 18 actually went into action; the rest broke down or ditched in shell holes. Those that ran terrified German defenders and helped take the villages of Flers and Courcelette.

“At dawn on Friday, 15 September 1916 tanks went into action for the very first time.”

The gains were modest — a few thousand yards — and many commanders were unimpressed. Yet the lopsided, slab-sided contraption had proved the concept that would dominate land war for the next century.