What happened in August 6th 1945?

Hiroshima suffered a nuclear attack

In August 6th of 1945 in Japan around 8:15 A. M. The city of Hiroshima was attacked by the airplane  B-12 which launched an uranium bomb called "little boy". Thousands of people were burned in the center of Hiroshima.
All the buildings in the square radius of 13km from the center of the explosion were totally destroyed. Around 78000 people and perhaps many thousands more died or were seriously injured in Hiroshima. 
Tokyo lost all contact with Hiroshima, so the Japanese government sent a reconnaissance mission to report what had happened,but Hiroshima was only a huge scarf in the earth,surrounded by the fire and smoke. 

 Hiroshima after the explosion.