Article: At the Battle of Mars-la-Tours, the Prussian 12th Cavalry Brigade, commanded by General Adalbert von Bredow, conducted a charge against a French artillery battery. The attack was a costly success and came to be known as "von Bredow's Death Ride", which was held to prove that cavalry charges could still prevail on the battlefield. Use of traditional cavalry on the battlefields of 1914 proved to be disastrous, due to accurate, long-range rifle fire, machine-guns and artillery. Von Bredow's attack had succeeded only because of an unusually effective artillery bombardment just before the charge, along with favorable terrain that masked his approach.

Now answer this question: What military tactic proved to be unsuccessful on the 1914 battlefields?
Use of traditional cavalry