Watch Hiroshima Full Movie Free Online 123Movies. The documentary recounts the world's first nuclear attack and examines the alarming repercussions. Covering a three-week period from the Trinity test to the atomic bombing of Hiroshima, the program chronicles America's political gamble and the planning for the momentous event. Archival film, dramatizations, and special effects feature what occurred aboard the Enola Gay (the aircraft that dropped the bomb) and inside the exploding bomb.