In 1915 Europe was in the midst of World War I and was at a stalemate caused by trench warfare. There was a need for new and revolutionary weapons to end the dilemma. The British found a solution to this problem by inventing tanks. The invention of the tank had numerous pros and cons, but it ultimately changed warfare. Tanks were built for the purpose of traversing through trenches. Trenches were becoming a literal wall and prevented either side from advancing. Tanks were the solution to the predicament that was the Western Front. The first prototype was called Mark I and was tested for the British Army in the September of 1916. Tanks were progressive and enabled many new tactics. They used caterpillar tracks which had a less likelihood of becoming stuck due to sinking. Tanks offered protection against firearms and intimidated German infantry men that were shocked deeply by the fact that they cannot destroy a tank with machine gun alone. Tanks were also great for accompanying infantry to protect them. There were also cons that went along with the use of tanks. Tanks were very slow, moving at a rate of four miles per hour; casual human walking speed. They were mechanically unreliable, and broke down frequently. Most of the time tanks were hot, numbingly loud and generally uncomfortable for the crews. After the British introduced the tank into the war other countries had their own variations. France launched their first tank, the Schneider CA1, shortly after Britain had introduced the. Mark I. These tanks were the same as British tanks in most aspects, except for that they moved faster by 1 mph. Close to the end of World War I, Germany had their own tank. The A7V, nicknamed "The Moving Fortress" by the British because of the shape of the hull, was entered into war in 1918 and were in action for eight months. One hundred vehicles were ordered during the spring of 1918, but only 21 were delivered.