Why is world war 2 considered the most destructive war in history?

World War II is considered the most destructive war in history due to its unprecedented scale, resulting in an estimated 70-85 million fatalities, which included both military personnel and civilians. The war spanned multiple continents and saw widespread atrocities, including the Holocaust and the use of atomic bombs on Hiroshima and Nagasaki. Additionally, it caused massive infrastructure damage, economic collapse in many regions, and long-lasting geopolitical shifts that shaped the modern world. The sheer intensity and global reach of the conflict set it apart from previous wars.