During which battle did nearly 20,000 British soldiers die on the first day?

The Battle of the Somme, fought during World War I in 1916, is historically significant for the staggering casualties experienced on its first day. On July 1, 1916, British forces suffered nearly 20,000 fatalities, making it one of the bloodiest days in British military history. This battle was part of a larger Allied offensive intended to relieve pressure on the French forces at Verdun and to weaken the German army. The extensive loss of life occurred due to a combination of surprise attacks, pre-battle artillery bombardments that failed to destroy German defenses, and the use of outdated tactics in the face of modern machine gun fire. The catastrophic first day underscored the horrific nature of trench warfare and marked a turning point in military strategies during the war.