War after War destroyed earth and its living beings to a extend that it was said that if there will be World War 3 then the earth will get destroyed forever and entirely, rest we all will too get destroyed.
The most dangerous Bombing attack, costed so much destruction mentally on mankind, but also physically on the people living there.
Here's a video studying the negative after effect of the bombing.
The important lesson learnt here is that first of all we should respect science and then comes the ethics and what about being kind and forgiving but not forgetting.