American soldiers in the First World War
U.S. Army/Public Domain
Anyone who has ever studied history knows that war makes up a large part of the human story. Believe it or not, however, the amount of wars has actually gone down in the last 100 years!

War has not always been a part of the human experience. Before the Neolithic Revolution--when human beings learned how to farm some 8,000 years ago--there is little evidence of human beings fighting each other.

Why did human beings ever start to go to war?

Because of property. When humans began to live in villages to farm, they started to own land. Money was soon created and people used war to gain land and money.

Fighting and warfare has almost always been tied to the taking of land and property.

There are several types of war that have been used throughout history:

1. Conventional War: This is the most common of all war in which countries formally announce war against another country with an army.

2. Total War: This is when a war includes all aspects of society and is conducted by using everything a country has.  In this type of war, rules of war are broken and cities and people are targeted. World War I and II are prime examples.

3. Civil War: This is a war when people in a country go to war against each other. In the United States, the American Civil War was fought between the North and the South over issues regarding slavery.  Most modern states have experienced civil war in one way or another. Civil Wars are currently happening in South Sudan, Syria, Afghanistan and Iraq.

4. Guerrilla War: This is a type of war fought by small groups against larger, more technologically advanced armies. In this type of war, the smaller group hides and sets traps for the larger army. The Vietnam War is an example of guerrilla warfare.

5. Cyberwar: This type of warfare involves the use of computers and the internet to attack the computer systems in other countries.  The spreading of computer viruses and the hacking of computer networks are the main activities in cyberwarfare.  In 2016, hackers in Russia broke into various components of the U.S. election system. To see a map of current cyberattacks, click here.

Sometimes in war weapons of mass destruction are used. These weapons include chemical weapons, such as mustard gas that was used in World War I and sarin, a toxic nerve agent that was used most recently in Syria.  Biological weapons spread disease among populations. The Mongols famously catapulted bodies infected with the bubonic plague over city walls, for example.

Nuclear weapons are the newest type of weapon capable of inflicting mass destruction. Developed first by the United States in World War II, two of these weapons were used on the cities of Hiroshima and Nagasaki in Japan. Today, there are 9 counties that have nuclear weapons.

This graph shows the trend of war from 1945 to 2014:

Source: Slate Magazine

Currently, renewed conflicts in Syria, Afghanistan and central Africa has dominated the news. Warfare is a fact of life in many war-torn areas.  Civilians suffer the most in modern war because cities are often targets. In World War II, more civilians died in war than did soldiers.

Check out the map below for current global conflicts: