A war is an armed conflict between governments, states, social groups and/or paramilitary groups (insurgents, militias, etc.). War causes extreme violence and destruction of property. A war can have a death toll as low as a few hundred or reach millions. Wars have been fought throughout human history. Technology advances have made modern day wars more high-tech. Modern military leaders have the ability to kill the enemey with the push of a button.

Wars are fought over resources, ideas and religious beliefs. For example, Japan attacked the USA during World War 2. Japan wanted to cripple the US Pacific Navy to get access to commodities in South Asia. The Cold War was a result of the opposing political beliefs of the USA and the Soviet Union. The Crusades were religious wars fought between Christians and Muslims. They fought over what they believed to be the Holy Land.

War is terrible and there is a major toll for all involved parties. Civilians feel the most pain and suffering. In modern warfare, nuclear weapons still pose a threat to humanity. In 2014, all nuclear powers had over 15,000 nuclear weapons. That is enough to put our planet into a nuclear winter, and kill billions.