World War2, the darkest phase of world history. New generation kids knows about world war 2 because of the living signs in hirozima and nagasaki. World War 2 was one of the deadliest war witnessed by human kind.
World of technology is growing at a steady. Nuclear weapons are considered as one of the greatest achievement by humans. According to me, it is one of the deadliest achievement because it could be used against our mother earth.