Why was Hiroshima a turning point for World War 2?

Because after the bombing of Hiroshima and Nakasaki, Japan finally surrendered. This ended the war in the Pacific Theater and because the war in Europe had already ended, WWII had ended entirely.

AnswerIt wasn't. It was the ending point of the war, not the turning point. Another stabLtCol Jimmy Doolittle's raid on the Japanese homeland in April, 1942, demonstrated to the Japanese that their homeland was vulnerable. It was more of a moral victory than a military one, but many believe that this bombing raid forced the Japanese to accept the fact that they were not invincible and to take on a more defensive strategy in the war. I'm not sure this was a "turning point" per se in the war, but it was certainly a significant turn of events.