This Is the Deadliest Battle in World History

The 872-day Siege of Leningrad marks one of the darkest periods of World War II. Instead of invading and occupying the city now known by its original name, Saint Petersburg, the Nazi Wehrmacht (aided by its Finnish allies) blockaded and bombarded this industrial center for months. Hundreds of thousands of Leningraders died from starvation, brutal winter weather, and disease, and some of the most desperate resorted to cannibalism.

The Battle of the Somme, named after a river, is one of three World War I battles that made this list. This British-French operation was intended to defeat the Germans on the Western Front, but it turned into a brutal fight of attrition for which there was no clear winner. The British suffered more than 57,000 casualties (including 19,240 soldiers killed) in the first day of fighting alone in the battle that raged for more than four months.

The Battle of Stalingrad is one of six World War II battles on this list and one of five that involved the Red Army either beating back the Nazis or marching to Berlin.

Hitler was determined to take Stalingrad (now called Volgograd) on the Nazi drive to smash Russian forces and seize oilfields in the Caucuses. But Stalin was equally determined to hold the city at all costs. The Red Army succeeded, but Russian troops paid dearly for the victory after months of urban warfare among the ruins and rubble of the bombed cty.

Operation Ichi-Go, the largest and bloodiest military operation in Japanese history, involved three major military clashes between the Imperial Japanese Army and the National Revolutionary Army of China (with air support from U.S. forces) that took place over eight months in three Chinese provinces.

“Ichi-Go” is a part of a Japanese idiom that means “one time,” showing the Japanese viewed these fights as a one-time opportunity to seize Allied airfields and open up land routes to reduce dependence on maritime military assets. The Chinese refer to it as the Battles of Henan-Hunan-Guangxi.

Hitler’s refusal to surrender, perhaps fueled by his drug use as some historians claim, meant the Allies had to pound their way into the heart of Germany. Nazi forces pushed back at almost every opportunity. By the spring of 1945, the Red Army had Belin in its sights after losing millions of soldiers and civilians over the course of World War II.

The Red Army’s brutality on its march to Berlin (revenge for Nazi barbarism) meant many Nazi troops and civilians believed they would be executed if they surrendered to the Russians. This led to a prolonged fight to the death in any encounter with Russian troops.

The surprise Nazi invasion of the Soviet Union that began on June 22, 1941 involved more 10 million combatants over several months, a staggeringly high number by any standard of warfare. Some 5.5 million Russians faced off against 3.5 million Germans and 700,000 German-allied troops, mainly from Finland, Romania, Hungary, Italy and Slovakia.

The German Spring Offensive of 1918 is one of three World War I battles on this list and one of eight on this list instigated by German military offensives. After the Russian resistance collapsed in 1917, the Germans pivoted westward in an attempt to end the war before U.S. military power could be fully deployed to Western Europe. After nearly four months of barbaric trench warfare, the Germans failed in their effort to win the war before the U.S. arrived to help its European allies defeat the German Empire.

The Battle of Dnieper (named after a major River in Eastern Europe) is yet another battle on this list in which the Soviets took heavy casualties defending against German attacks. The Nazis attempted to build an “East Wall” along the western shore of the Dnieper in order to block Russian advances.

From August to December 1943, 4 million soldiers on both sides engaged in fierce fighting. Though the Red Army took more casualties, the Russians managed to punch through the German wall, making the Nazi withdrawal from the USSR inevitable.

The Brusilov Offensive was another Russian victory against the Germans that involved heavy Russian casualties. Named after the Russian general who spearheaded the military victory, one of the most successful in World War I, the summertime offensive sparked the demise of the Habsburg Empire. Germany sent military reserves to support the Empire, which weakened them on the Western Front.

The 13th century sacking of Baghdad, then one of the world’s great intellectual and scientific centers, is incomparable. The other battles on this list raged for months (and in one case, for more than two years) and took place from 1916 to 1945, during the World Wars. But the brutality in this case was swift and horrendous to the civilian population. After a 12-day siege, the tribal horde entered the city and indiscriminately killed almost anyone they could find. The short battle marked the end of the Islamic Golden Age.