Analysis of information sources in references of the Wikipedia article "List of peace activists" in English language version.
The turning point in Ferlinghetti's life came in late September 1945 as he walked the streets of Nagasaki, Japan, six weeks after an atomic bomb was dropped on the city by his country's government. ... Among the 40,000 Japanese who were incinerated on the day of August 9 was one who was drinking tea at the time. ... Ferlinghetti picked up that person's teacup; it had flesh and bone fused into it. The cup has now sat on the mantelpiece of his home for 75-and-a-half years. ... In all his prodigiously creative works, he never missed the opportunity to chastise the absurdity of materialism, the obscenity of war and the soullessness of profit-driven destruction.
These experiences, particularly witnessing the aftermath of the Nagasaki bombing, turned Ferlinghetti into a lifelong pacifist and anti-war activist.