
Background and the initial attack
The Somme Offensive was the planned Franco-British attack that would coincide with simultaneous offensives along the Balkan, Eastern, and Italian fronts, designed to stretch the Central Powers' forces across all European theaters of the war. The German offensive against the French at Verdun, however, had resulted in a stalemate and saw much of the French support redirected from the Somme; therefore, the British part in the offensive switched from a supporting to a leading role. Allied artillery lay down a week-long, constant bombardment upon the German front lines, in an attempt to clear a path through the barbed wire in no-man’s-land, disrupt supply lines, and destroy the enemy trenches.Despite dropping around 1.7 million shells on the enemy, much of the barbed wire remained intact, and the British had underestimated the depth and stability of the German trenches, which were 15 meters (50 feet) deep in some areas. Additionally, it is estimated that 30 percent of these shells failed to detonate. Approximately 120,000 men went over the top at 07:30hrs on July 1, 1916, in what became the costliest day in British military history. The advance was more perilous than anticipated, and the fortified German machine gun positions cut down thousands of British troops. British and French offenses in the south did make some progress in the opening stages of the battle, however the bulk of the force was held back by the Germans. This set the trend for the next five months, with heavy and slow attacks resulting in limited territorial gains.
Technological advancements and new developments
The Somme Offensive marked a major milestone in the history of warfare, as it saw the first ever deployment of tanks in the Battle of Flers-Courcelette, on September 15. Almost 50 Mark I tanks were sent to the Somme, although not all made it into the field. When deployed, the tanks achieved mixed results; a small number were able to push through no-man's-land and make some territorial gains, yet many became immobilized due to the rough, muddy terrain. To many military leaders at the time, the tanks were deployed prematurely and too sparsely to have a meaningful impact, and the element of surprise had been negated by their ineffectiveness; it would take another year before tanks would see significant success in the war. In contrast, aircraft played an invaluable role in the Battle of the Somme. Not only did fighters launch attacks and air raids on the enemy lines, but the reconnaissance obtained from the air gathered information on enemy movements, and radio messages helped to orchestrate artillery attacks in live time. The importance of this reconnaissance also led to air battles between fighters of the Imperial German Flying Corps and the Royal Flying Corps, the latter of which maintained aerial superiority throughout the war.The attritional bombardment seen on the Western Front, combined with the static nature of trench warfare, led to a "new" phenomenon coined as "shell shock" in 1915. While this is now clearly defined as a psychological issue and a form of PTSD, doctors in 1914 failed to diagnose or understand the problem correctly, often believing it to be a physiological result of artillery blasts on nervous system. By the time of the Somme Offensive, however, military officials were forced to take the problem more seriously, and a series of mental hospitals were established to help the affected recover, and return them to the front lines. Some estimates suggest that as many as two-fifths of all British casualties at the Somme were shell shock related.