Although considerable conflict took place outside Europe, the European theatre (also known as the First European War) was the main theatre of operations during World War I and was where the war began and ended. During the four years of conflict, battle was joined by armies of unprecedented size equipped with new mechanized technologies, leaving millions dead or wounded. The European theatre is divided into four main theatres of operations: the Western Front, the Eastern Front, the Italian Front, and the Balkans Front. Not all of Europe involved in the war. Nor did fighting take place throughout all of the major combatants territory. The United Kingdom was nearly untouched by the war. Most of France was unaffected, as was most of Germany and Italy. Some large countries in Europe remained neutral for the entire war such as Sweden and Spain – the Great War passed them by without much impact. On the other hand, some countries were conquered (Serbia, Belgium, Romania). Other countries like Russia and the Ottoman Empire saw armies marching over much of their lands, with a great deal of resulting devastation. Although the United States did join the war, due to Great Britain's control over the Atlantic Ocean, the only fighting for the U.S. Army was in Europe on the Western Front. The American army was transported by ship across the ocean so it could fight the Germans in France. Western Front Germany planned to apply the Schlieffen plan. The Schlieffen plan was to attack France first since Russia wouldn't be able to mobilise quickly. Germany launched an offensive through Belgium, which made the British Empire declare war against Germany. France's Plan XVII - a concentrated offensive meant to overwhelm the German army - also failed. The Western front quickly became a military stalemate, claiming hundreds of thousands of lives on each side. This led to the armies digging in. Mobile warfare only resumed in the final months of the war. During the spring of 1918 the German army launched a massive offensive towards Western France with the aim of defeating France before American reinforcements arrived. Since Russia was in a civil war at the time many German divisions were sent to the Western front. The Germans advanced towards the Marne after the Micheal Offensive, Operation George, Gneisenau, and Blücher-Yorck. Major ground was taken in the German front taking many lands that they lost from Pre-Hindenburg Line,