The significant trial held after World War II to address war crimes was the Nuremberg Trials. These trials commenced in 1945, where prominent leaders of Nazi Germany were prosecuted for crimes against humanity, war crimes, and genocide. The Nuremberg Trials aimed to hold individuals accountable for their actions during the war, establishing that following orders was not a valid defense. They also set precedents for international law, leading to the establishment of the International Criminal Court and influencing how atrocities are prosecuted in subsequent conflicts.