The earthquake in the movie really happened in real life in Los Angeles three months before the bomb detonation in Hiroshima.
Kevin James met Eduardo Verástegui during the filming of this movie. The two got along so well that James wrote a character in Paul Blart: Mall Cop 2 (2015) specifically for Verástegui.
Emily Watson's third film that takes place during World War II. The other being The Book Thief (2013) and The Water Horse (2007). Note: Angela's Ashes also takes place during WW2.
When Little Boy imagines himself walking among the ruins created by the atomic bomb "Little Boy," the scene is shot in black and white, with his clothes and the atomic bomb staying red in color. Steven Spielberg employs this same technique in Schindler's List, which is most likely the inspiration.