In discussing World War I casualties, the focus is usually on the horrendous losses in attempts to break the trench war stalemate, especially at Verdun and along the Somme in 1916. Horrible as these were, the first months of the war were actually worse. France lost 75,000 dead in the first month, including 27,000 killed in a single day (August 22, 1914). 1914 was the worst year of the war for French casualties, even though the war didn’t start until August . Germany and Russia suffered similar losses, though British casualties did not really ramp up until the following year.
The reasons for this bloodbath are not hard to see. Tactics had been falling behind technology for a century. In 1914, the European armies had magazine rifles, really good machine guns, and quick firing artillery. Railroads and motor vehicles allowed enormous armies to be assembled and thrown into the furnace in short order.
Yet, French troops still wore their traditional red and blue uniforms, with soft kepis on their heads. French currassiers rode into battle in polished breatplates and similarly bright plumed helmets, but no European army had effective steel helmets.
The armies would very quickly have wiped each other out if not for the collective decision to abandon mobility and dig in for trench warfare.