Earlier in July, the 40th anniversary of the launch of Apollo 11 was celebrated. Today, however, another notable but deeply saddening event is remembered.

At approximately 8:15am on August 6th 1945, the U.S. B-29 bomber “Enola Gay” dropped its 4,000 Kg uranium bomb onto the Japanese city of Hiroshima. After freefalling for 57 seconds, the “Little Boy” detonated at an altitude of 580 metres. The calm and sunny Monday morning was shattered by a white light that burned patterns of clothing onto skin and the shadows of bodies onto walls.

The blast wave that followed destroyed almost every building within a three mile radius and the searing heat set off a raging firestorm. With a power of 13 to 16 kilotons, the bomb killed 66,000 people immediately, and by the end of 1945 the death toll was thought to be 140,000.

To mark 64 years since the atomic bombing of Hiroshima, Boston.com takes a poignant look at the event. There are 34 pictures in total – see them at The Big Picture.