The 20th century saw the most brutal wars in human history. Here is a list of battles which caused the largest number of casualties.
Battle of Stalingrad
The Battle of Stalingrad (23 August 1942 – 2 February 1943) is the bloodiest battle in human history, causing an estimated 2 million casualties in a space of a little more than five months. Fought during World War II between the Soviet Union and Nazi Germany for control over the city of Stalingrad (now known as Volgograd), the brutal fighting eventually culminated in a Russian victory which proved to be a decisive moment in war. The Russians suffered the most casualties ( +1 million).
Battle of Moscow
The Battle of Moscow (2 October 1941 – 7 January 1942) was fought between Nazi Germany and the Soviet Union during World War II. The German attempt to capture the Russian capital, codenamed ‘Operation Typhoon,’ saw over 1.6 million casualties. The Russians successfully repulsed the German attack, although at great cost (1.2 million casualties).
Battle of Somme
The Battle of Somme (1 July – 18 November 1916) was fought between the German Army and British-French alliance during World War I near River Somme in France. The biggest battle of the Great War saw 1.2 million casualties in total. It was also the first battle in the history of warfare that saw the use of tanks.
The Belorussian Strategic Offensive Operation, code-named Operation Bagration (22 June – 19 August 1944) was a Russian attempt to vacate German forces from Byelorussia (currently Belarus) that saw intense fighting causing 1.1 million casualties. A major chunk of the German army in the region was destroyed in the Russian offensive resulting in a decisive Soviet victory.
Battle of Gallipoli/ Battle of Çanakkale
The Battle of Gallipoli/ Battle of Çanakkale, also known as the Dardanelles Campaign (17 February 1915 – 9 January 1916) was fought between the Ottoman Empire and Western allies (Britain, France) during World War I. The primary objective of the British/French invasion was to capture the Gallipoli peninsula and Turkish capital Istanbul.
The intense fighting saw close to 0.5 million casualties and resulted in a major Turkish victory. Founder of modern Turkey, Mustafa Kemal, who was a colonel at the time, personally participated in the combat.