In December 1914 the First World War found itself faced with a dilemma on the Western Front that neither the Triple Entente nor the Triple Alliance had expected. The war had reached a stalemate, a state in which both sides are so balanced that neither can break through against the enemy. Technological advances played a major role in creating the stalemate through powerful defensive weapons such as machine guns and artillery, this caused "trench warfare" (BOOK 48). Trench warfare occurs when troops on both sides are protected from enemy firepower through trenches. Many technological advances also attempted to break the stalemate during the war with tanks, gas, and planes, but failed. The stalemate was eventually broken through a combination of improved technology, new strategies, and the blockade of German ports. Creating Stalemate The stalemate on the Western Front had developed in December 1914 due to new advances in defensive weapons where both sides had developed lethal weapons. such as machine guns and artillery, which later led to trench warfare. The machine gun was a very dominant weapon in World War I. It could kill hundreds of men per minute thanks to its rapid rate of fire of 600 bullets per minute. However, machine guns used in World War I weighed between 30 and 60 kg, required four to six operators, and could heat up very quickly; clearly not very effective as an offensive weapon (Duffy, Michael. "Machine Guns.") Machine guns were only effective for defense as they were extremely heavy and required a lot of ammunition to attach to the ground. This made attacking and moving with machine guns very difficult. Artillery was even more deadly as a defensive weapon and was one of the most important weapons of the First World War as it was the cause of most human losses. Artillery ranged from field artillery to heavy, long-range artillery that could fire long distances and trap enemies in their trenches. A very effective weapon during the war was also the trench mortar, which was a "tube" that fired at a vertical angle (greater than 45 degrees) and could therefore be fired within the safety of the trench, unlike the artillery. All these new technological advances have made trenches almost impossible to attack, but they have also kept each side trapped in their own trenches.