War crimes are violations of laws in armed conflict and include murder, ill-treatment of civilians or prisoners of war, destruction of cities, and other acts. They have been commonly committed throughout history, such as the use of poison gas in WWI and the Holocaust in WWII. Both Axis and Allied powers committed atrocities in WWII. More recent examples include crimes during the Vietnam and Civil Wars, such as targeting civilians. Perpetrators rationalize war crimes as intimidation, revenge, or following orders to survive. However, war crimes are often not punished because winners write history and decide who to prosecute, such as at the Nuremberg Trials. Some believe any means are acceptable to achieve victory in war.