Explanation:

Hiroshima Day marks a destructive historical event that took place in Hiroshima, Japan in 1945 during the World War II when USA dropped atomic bomb on the city.  On August 6, 1945, the US dropped the nuclear weapon, ‘Little Boy’ on the Japanese city of Hiroshima around 8:15 a.m. Since then, the day is observed as an occasion to mourn the thousand deaths and pays tribute to the survivors and succeeding generations.