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The 20 Worst Wars in World History


Warfare, regardless of how huge or small it is, severely impacts people directly or indirectly involved in the War. In world history, there have been many wars all over the globe that led to the death of hundreds, if not millions, of people. Like in many wars, most people who die are innocent civilians. There are many reasons why wars arise, including poor government leadership, religion, poverty, and territory disputes. Even though War is generally destructive, some wars in history have proven devastating. Other than many deaths, these wars have led to widespread destruction. This piece closely examines the 20 worst wars in world history. We analyze every War's origin of the conflict, the casualties, and the death toll.

20. Thirty Years' War (Number of Deaths: approximately 8 million)

The Thirty Years' War was fought in Central Europe between 1618 and 1648. This War was among the European powers of that time. According to Worldhistory, initially, this War was mainly between Catholic and Protestant states from the seceding Holy Roman Empire. Later, it spread so fast to involve most parts of the European continent. The War had a heavy deployment of large armies, resulting in many individuals' deaths the following year. This made the Thirty Years' War one of the bloodiest conflicts in human history.

19. Chinese Civil War (Number of Deaths: approximately 8 million)

This civil War was a conflict that took place in the 20th century between the Republic of China and the Communist Forces. The War happened in two different phases due to World War II. The initial phase of the Chinese Civil War took place between 1927 and 1936, while the second one happened between 1946 and 1950. This conflict was a result of the fall of the Qing Dynasty. As communist forces and the government tried to seize power in the vacuum left, conflict ensued immediately.

18. The War of Kalinga (Number of Deaths: 100,000)

The War of Kalinga is evidence of one of the bloodiest feuds in humankind's history. This grievous War took place in 261 BCE during Maryan Empire's reign. The conflict was between the Kalinga State of India and emperor Ashoka. The War was brought about by emperor Kalinga's ambitions to claim Kalinga as part of the Empire. Ashoka deployed a heavy army that dealt a blow to Kalinga's army and became victors. However, the aftermath of the War was so devastating and changed the emperor in a big way. He vowed never to use violence to resolve a conflict after experiencing the impact of the War.

17. The Russian Civil War (Number of Deaths: more than 9 million people)

Between 1917 and 1926, the Russian Civil War involved the White army (Nationalists) and the Red army (communists) forces. After the end of the Russian Empire, Bolshevik forces engaged nationalist troops to control Russia's interior. The consequences of this War were so disastrous in terms of lives lost and property damaged. For around six years, the disastrous War caused Russian against Russian rivalry, with many battles erupting from the country's interior. The communist regime emerged victorious but ushered in a period of repression and terror in the following decades.

16. Iraq-Iran War (Number of Deaths: 1 million)

This War was an armed rivalry between Iraq and Iran that lasted from 1980 to 1988. During the 20th century, this was the longest conventional War. This War started after Iraq invaded Iran through land and air on 22nd September 1980. It later ended with a stalemate on 20th august 1988. Regarding the tactics that this War used, it has similarities with World War I since it involved large-scale trench warfare, bayonet charges, and chemical weapons.

15. The Civil War of America (Number of Deaths: 620,000)

Looking at it from the perspective of casualties, this War was among the bloodiest and the deadliest battle ever experienced in the history of the world. It was a war between the Union and the confederacy states. This gruesome warfare created a scenario of simmering tension between the northern and southern states of America. The feud happened between 1861 and 1865, after which the Union emerged winners. The exact number of deaths from this War is not available. According to history, estimates the death toll at 620,000 people.

14. Japanese Invasion of Korea (Number of Deaths: 1 million)

The Japanese Invasion of Korea happened between 1592 and 1598, comprising two separate but closely linked operations. The first invasion took place in 1592, while the second one happened in 1597. This feud ended in 1598 after Japanese forces retracted, leaving behind at least 1 million casualties on the side of Koreans.

13. The Second Congo War (Number of Deaths: 5.4 million people)

Between 1998 and 2003, the second Congo war was among the deadliest in human history. According to statistics, the War lasted for five years and caused the death of approximately 5.4 million people. This War started in the Democratic Republic of Congo a few years after the first Congo war. Even though genocides were the leading cause of the deaths, other factors such as famine and diseases also accounted for these deaths.

12. Siege of Jerusalem (Number of Deaths: 1.1 million)

This is among the oldest wars on our list, as it happened in 73AD. The siege of Jerusalem was a move by the initial Jewish-Roman War. In this War, the Roman army conquered Jerusalem, which Jewish defenders had previously occupied. This War ended with the destruction of Jerusalem's Second Temple and the city's sacking. According to military-history, the War claimed the lives of 1.1 million civilians both from violence and other factors like famine.

11. Huguenots Wars (Number of Deaths: 2-4 million)

Famously known as the French Wars of Religion, the Huguenot Wars took place between 1562 and 1598. This was a period of military operations and civil infighting. The War was mainly between Protestants (Huguenots) and Catholics. The actual number of wars that were fought during this time and their exact dates are still under debate by historians. However, this War is believed to claim 4 million lives.

10. Dungan Revolt (Number of Deaths: 8- 20.8 million)

This was primarily a religious and ethnic feud between the Huis (Chinese Muslims) and Hans (a Chinese ethnic group with East Asia origins). The War happened in the 19th century and took place in China. This conflict came about as a result of a conflict that involved bamboo poles. This rivalry arose when a ham business person who was selling to a Hui didn't receive money for the goods. More than 20 million people are believed to have died in the revolt. The leading cause of these deaths was not necessarily genocide but famine and natural disasters.

9. Mexican Revolution (Number of Deaths: 1-2 million)

Spanning ten years, the Mexican revolution took place between 1910 and 1920. It was an armed struggle that entirely changed the Mexican government and culture. From its population of 15 million, the losses incurred by the War were high even though numerical estimates vary wildly. The Mexican revolution was an important event and one of the major upheavals in the 20th century.

8. Taiping Rebellion (Number of Deaths: 20-30 million)

Commonly known as the Taiping Civil War, this was a massive rebellion in China in the 1850s. The War was between the Manchu-led Qing dynasty and a Christian millenarian movement dubbed the Heavenly Kingdom of Peace, according to Britannica, it took place between 1850 and 1864. Even though there are no precise figures for the death toll, it is believed that this rebellion swept away 30 million soldiers and civilians. Most of the deaths emanated from famine and plague.

7. Napoleonic Wars (Number of Deaths: 3.6-6 million)

Napoleonic wars occurred between 1803 and 1815, a collection of main conflicts. It pitted the then French Empire (led by Napoleon Bonaparte), a political leader, and a French military against European powers created into different coalitions. Napoleon fought 60 battles during his military career and lost only seven towards the end of his reign. The total European wars could have gotten to the deaths of 5 million military personnel, some emanating from disease.

6. Conquests of Tamerlane (Number of Deaths: 8-20 million)

Known by another name as Timur, the Tamerlane was a military leader and a Turco-Mongol conqueror. Slightly past the mid-14th century, Timur led military campaigns in Western, Central, and south Asia, southern Russia, and the Caucasus. He came out as a mighty ruler in the world of Muslims after conquering the Mamluks of Syria and Egypt. According to history, Timur's military campaigns account for the death of 17 million people.

5. An Lushan Rebellion (Number of Deaths: 13-36 million)

This is another brutal war that happened in current China. The rebellion was against the Tang dynasty, and according to totallyhistory, it lasted between 755 AD and 763 AD. The An Lushan rebellion accounted for many people's deaths, significantly reducing the population of Tang's Empire. However, there is no exact figure for the death toll. Some scholars assume that at least 36 million people died during this rebellion. This was two-thirds of the Empire's population.

4. Three Kingdom War (Number of Deaths: 36-40 million)

This was a collection of armed conflicts in old China between AD 220 and 280. During the War, three states were vying for the country's power. They included Wu, Wei, and Shu as they tried to unite the nations and take control. This was one of the bloodiest wars in Chinese history, marked by severe battles that could have killed 40 million people.

3. World War I (Number of Deaths: 18 million)

World War I happened from July 1914 to November 1918. This was a global war emanating from Europe, gradually drawing in the globe's economic giants and setting up two opposing alliances. These were the Central Powers and the Allies. Statistics indicate that the War claimed the lives of 11 million military personnel and nearly 7 million civilians. Close to two-thirds of the military played a part in the War as opposed to the conflicts in the 19th century, where deaths were mainly a result of diseases.

2. Conquest of the Americas (Number of Deaths: 8.4-138 million)

Europeans colonized America, and this began technically in the 10th century. This was when the West Norse sailors settled briefly in the regions on modern Canadian shores. However, the period between 1492 and 1691 is the one that refers to the conquest of the Americas. For 200 years, millions of people lost their lives. They were killed in the battle between naïve Americans and the colonizing powers. Exact figures of the lives lost are missing, however, due to the disagreement on the demographic size of the ancient population.

1. World War II (Number of Deaths: 60-85 million)

World War II was a fight that started from 1939 to 1945. As the name says, it was a global war involving most nations, including the great powers. In history, this War has remained the most spread out and directly impacted more than 100 million people in more than 30 countries. The War was marked by the massive loss of lives among civilians. It included the strategic bombing of population centers and industrial centers. According to NCBI, the War resulted in 60 and 85 million deaths. World War II has remained one of the deadliest warfare in world history.


One of the things that humankind did from the start of time was fight with one another. Many times, the fight got out of hand and consumed innocent lives. As stated in the beginning, wars erupt for different reasons, including religious conflicts, ruthless governance, territorial disputes, and many more. During wars, people die from genocide, famine, or natural disasters. The most affected lot, in this case, is the civilians. The lesson we learn from the list of wars above is that does not yield any positive results. Instead, it destroys property and causes massive loss of lives.

Dana Hanson

Written by Dana Hanson

Dana has extensive professional writing experience including technical and report writing, informational articles, persuasive articles, contrast and comparison, grant applications, and advertisement. She also enjoys creative writing, content writing on nearly any topic (particularly business and lifestyle), because as a lifelong learner, she loves to do research and possess a high skill level in this area. Her academic degrees include AA social Sci/BA English/MEd Adult Ed & Community & Human Resource Development and ABD in PhD studies in Indust & Org Psychology.

Read more posts by Dana Hanson

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