The 20th century featured some of the deadliest battles and wars in history, and we’re not even including the world wars here. Some of them – like the Nigerian Civil War – would result in the deaths of millions of people, many of them civilians that had nothing to do with the many underlying causes of these brutal conflicts. Here are 10 of the bloodiest non-World War battles of the century
10. Battle Of Warsaw
The Battle of Warsaw is also sometimes called the Miracle on the Vistula, fought between August 12 and 25, 1920, during the Russo-Polish War. It began with the Bolsheviks’ attempt to export their revolution to nearby regions and secure their borders, with Poland being one of their oldest and strongest enemies in the region. Poland, on the other hand, fought to assert its newly gained independence and expand eastward.
As the Red Army approached Warsaw, the Poles, led by General Józef Pi?sudski, defended the city while launching a flanking maneuver from the south, encircling and overwhelming the Red Army. The Polish victory outside Warsaw is still remembered as a victory of a weak, outnumbered enemy against a vastly-superior military force, although at a heavy price. The battle resulted in the deaths of possibly 15,000 – 25,000 Soviet soldiers, with up to 5,000 dead on the Polish side.
9. Tet Offensive
The Tet Offensive of January 1968 was a major military campaign of the Vietnam War launched by North Vietnamese forces and the Viet Cong. It involved simultaneous attacks on South Vietnamese cities, military installations, and towns, with around 85,000 participating troops. The offensive aimed to break the stalemate in the war and achieve either a collapse of the South Vietnamese government or a withdrawal of United States forces from the conflict.
Despite advance warnings on the southern side, the attacks were larger and more intense than expected, briefly capturing parts of Saigon and 36 provincial capitals, including the ancient capital of Hue that was occupied until February.
The northern forces suffered heavy casualties by the end of it, with estimates suggesting up to 50,000 troops killed. Conversely, U.S. and South Vietnamese losses were far fewer. Although a military failure, the offensive was a propaganda victory for North Vietnam and Viet Cong, as it weakened the South Vietnamese government and adversely affected its military alliance with the United States.
8. Battles Of Khalkhin Gol
Tensions between the Soviet Union and Japan started flaring up in the late 1930s, particularly along their shared border along the Khalkhin-Gol river in Mongolia. The largest clashes – now known as the Battles of Khalkhin Gol – happened between May and September, 1939, when Soviet forces crossed the river to assert control over disputed land, encountering fierce resistance from the Japanese Sixth Army. Believing that the river marked the border, the imperial Japanese forces launched a series of attacks across the front, decisively pushing back the initial Soviet advance.
By the end of August, however, Soviet forces under General Georgy Konstantinovich Zhukov outnumbered the Japanese two to one, with superior tanks and artillery. His envelopment and destruction strategy proved successful, inflicting heavy casualties on the Japanese army. Despite the Japanese commander preparing a counteroffensive to respond to it, a ceasefire was declared in Moscow due to the outbreak of war in Europe. On the other hand, the skirmishes convinced the Japanese that a protracted conflict with the Soviet Union was unfavorable, which in turn influenced their decision to attack the United States in 1941 instead of Siberia.
7. Battle Of Teruel
The Battle of Teruel took place during the Spanish Civil War, lasting from December, 1937 to February, 1938 amidst some of the most severe winter conditions of the war. It was centered around the city of Teruel that changed hands between Republican and Nationalist forces many times throughout the conflict.
It was one of the deadliest phases of the civil war, marked by intense artillery and aerial bombardment that resulted in heavy casualties on both sides. Many died due to the effects of the winter, resulting in a total number of 110,000 deaths on both sides over the course of two months.
6. Battle Of The Marshes
The Battle of the Marshes, or Operation Kheibar, was fought during the Iran-Iraq War between February and March 1984. The main battleground was the Hawizeh Marshes towards the north-east of Basra, where Iran launched a new offensive after many earlier unsuccessful operations. They initially faced heavy losses with human wave attacks, resulting in over 15,000 casualties and slow progress. Iranian forces adapted over time, however, with more-successful amphibious assault offensives with the help of their 92nd Armored Division.
While the Iranians eventually nearly broke through the Iraqi lines, they were eventually pushed back to these marshes and Majnoon Island, where it turned into a massacre. It was a pyrrhic victory for Iran, as they succeeded in removing the Iraqis from the territory but still suffered losses of over 200,000 men in one of the most brutal military offensives of the century, at the cost of about 10,000 soldiers on the Iraqi side. It was also when Iraq deployed chemical weapons like mustard gas on a mass scale, giving the war a whole new horrifying dimension.
5. Battle Of Dien Bien Phu
The Battle of Dien Bien Phu was the most important battle of the First French-Indochina war, fought between the French colonial government and the Vietnamese nationalist forces under the command of Ho Chi Minh. It began on March 13, 1954 and lasted until May 7, bringing a decisive end to French rule in the region.
By November, 1953, thousands of French forces had taken control of an airstrip in the Dien Bien Phu valley in the northwest of Vietnam. They aimed to cut off Vietnamese supply lines and support a growing insurgency in Laos that matched with their goals, hoping to draw the Viet Minh into a conventional, open battle they believed they could win.
However, they had greatly underestimated the capabilities of General Vo Nguyen Giap’s Viet Minh forces that soon surrounded the valley and began artillery bombardment that lasted for four months. The siege against this single French position was relentless and brutal, and despite support from the United States, the French garrison ultimately succumbed to the overwhelming assault. Around 10,000 French troops out of 15,000 lost their lives during the battle, including 2,200 that died during the battle and more than 7,000 that succumbed to the harsh conditions of Vietnamese prisoner-of-war camps.
4. Lebanese Civil War
The Lebanese Civil War was a multi-faceted conflict that lasted for more than 15 years. From 1975 to 1990, anywhere between 150,000 to 200,000 people – mostly civilians – died in the war that left Lebanon in ruins, making it one of the deadliest conflicts of the century in the Middle East.
It began with an attempted assassination of a Christian Phalangist leader, triggering clashes between Palestinian-Muslim forces and Phalangists. Syria intervened in 1976, aiming to meet its own goals in Lebanon, followed by the entry of various other Arab and Middle-Eastern countries. Israel invaded in 1982 to eliminate the presence of the Palestinian Liberation Authority in the country, leading to brutal civilian massacres in refugee camps and involvement of the United States and United Nations to end the conflict.
3. Battle Of The Ebro
The Battle of the Ebro was fought between July 25 and November 16, 1938, marking the final and bloodiest chapter of the Spanish Civil War. It began when Republican forces launched a surprise attack after crossing the Ebro river at various points and breaking through the defensive lines of General Franco’s army.
The battle lasted 115 days and resulted in about 130,000 casualties on both sides. According to some reports from the time, many soldiers that died during this time still remain buried in unmarked locations across the front. While the Republican forces saw some early successes, they were ultimately defeated by Francoist troops that countered with overwhelming bombing runs and frontal assaults.
2. Huaihai Campaign
The Huaihai Campaign was an important battle of the Chinese Civil War, fought from November 1948 to January 1949 in the valley of the River Huai. The campaign marked a decisive turning point of the entire conflict, as it was here that the Communist forces – led by Chen Yi and Liu Bocheng – gained the upper hand against Nationalist troops.
The final and decisive battle of the offensive happened in and around Yungchung, resulting in the capture of 327,000 Nationalist prisoners, including their commander General Tu. At the same time, Liu Bocheng targeted the Nationalist stronghold of Ch’inglungchi, which ultimately fell on January 22 and opened the way for further Communist advances towards Nanjing and Shanghai.
The Battle at Xuzhou witnessed the deaths of about half a million Nationalist troops, dealing a major blow to their positions north of the Yangtze River. The victory during this campaign played a crucial role in the ultimate Communist conquest of China.
1. Nigerian-Biafran War
The Nigerian-Biafran War, also called the Nigerian Civil War, began in 1967 when the Republic of Biafra in the southeast of Nigeria seceded from the country. It was a fierce conflict marked by widespread violence against civilians, fueled by long-standing regional tensions like ethnic competition, educational inequality, and economic disparities.
Biafra – largely populated by displaced Igbo people – seceded after political turmoil and two failed coup attempts, leading to fighting between the secessionist state and Nigeria’s government. The war escalated quickly, and while Biafran troops made some initial advances, they were soon pushed back by the might of the heavily-armed federal Nigerian forces. International efforts to mediate and provide humanitarian aid were proven ineffective due to the scale of the war that ultimately cost the lives of anywhere between 500,000 to 3 million people.