Crimes against humanity occur based on aggression carried out systematically against the civilian population. The most common example to this day is the Holocaust when the Nazis systematically wiped out six million Jews.

In 1945 the London Statute was agreed upon, establishing the basis for the Nuremberg Tribunal. Article 6 of that statute spoke of crimes that would be possible to be tried by this court, including crimes against humanity.

In 1998, the Rome Statute and the institution of the International Criminal Court were created, which consolidated the crime against humanity, genocide, and war crimes. These crimes include murder, extermination, deportation or forced displacement of a population, imprisonment, rape, sexual slavery, and forced prostitution, among other things. Also included are any acts considered planned and organized atrocities by authorities against civilians. The Rome Statute then confirmed the independence of crimes against humanity, and a war situation was unnecessary for anyone to be held accountable.

Crime against humanity was used as a response to the Holocaust. Still, the first time this designation appeared was during the Armenian genocide, where 500,000 civilians were deported, and more than a million died.

There is a discussion about crimes against humanity because some scholars believe that crimes that cause environmental disasters or social inequalities also qualify as acts that lead to mass death. In this way, the economic policies of some financial centers could be considered crimes in this sphere.

In 2001, slavery and enslaved person trading became a crime against humanity after the World Conference against Racism, Racial Discrimination, Xenophobia, and Intolerance.

In this context, it does not matter whether these crimes are committed before or during a war since the aim is to punish those who, in dictatorial or totalitarian regimes, use the state machine or a private organization to carry out serious violations of humanitarian rights in the event of a trivialized attack on the civilian population.

The International Criminal Court carries out the trial of those who commit crimes of this nature. Here it is worth pointing out that the International Criminal Court is an independent institution that does not judge countries but rather individuals.

First of all, the crime must be prosecuted and judged by the justice of the countries that are part of the Rome Statute, and only if there is a need in some situations can the case be taken to the International Criminal Court. Some of the circumstances are derived from the country's inability to adequately conduct criminal proceedings internally or its unwillingness to do so, as in the case of nations living under dictatorial rule.

When a crime against humanity occurs, the investigation can be started in three ways, the first being through the Prosecutor of the Tribunal, which currently (2023) is the British Karim Khan. The second is by communication from a country that is part of the treaty, and finally, through a decision of the UN Security Council that can report to the prosecutor any situation that falls within the court's competence.