History of Wars, War Crimes and Genocide in the 20th Century

A century (from the Latin centum, meaning one hundred; abbreviated c.) is a period of 100 years. Centuries are numbered ordinally in English and many other languages.

Genocide is intentional action to destroy a people (usually defined as an ethnic, national, racial, or religious group) in whole or in part. The hybrid word "genocide" is a combination of the Greek word génos ("race, people") and the Latin suffix -cide ("act of killing"). The United Nations Genocide Convention, which was established in 1948, defines genocide as "acts committed with intent to destroy, in whole or in part, a national, ethnic, racial or religious group".

History (from Greek ἱστορία, historia, meaning "inquiry, knowledge acquired by investigation") is the study of the past as it is described in written documents. Events occurring before written record are considered prehistory. It is an umbrella term that relates to past events as well as the memory, discovery, collection, organization, presentation, and interpretation of information about these events. Scholars who write about history are called historians.

War is a state of armed conflict between states or societies. It is generally characterized by extreme aggression, destruction, and mortality, using regular or irregular military forces. Warfare refers to the common activities and characteristics of types of war, or of wars in general. Total war is warfare that is not restricted to purely legitimate military targets, and can result in massive civilian or other non-combatant suffering and casualties.