Filmed in a house called "Cliff House" designed by famed architect Frank Lloyd Wright. It was the home of the film's producer/writer/director, Arch Oboler, and sat on his 360-acre ranch in the Santa Monica Mountains along Mulholland Highway. Outdoor scenes were filmed on his property as well as other nearby locations in the Santa Monica Mountains.
According to TCM's Robert Osborne, this is the first feature film to depict the aftermath of a nuclear holocaust.
The character of Eric, the bigoted quasi-Nazi, was a good warm-up for actor James Anderson, who would take on his most famous movie role, the monstrous Robert E. Lee Ewell, so memorably in To Kill a Mockingbird (1962) more than a decade later.
There is no "The End" title card. The following paraphrased Bible verse from Revelation 21 appears onscreen just before the end credits: "And I saw a new heaven / And a new earth... / And there shall be no more death / No more sorrow... No more tears... / Behold! I make all things new!"
The verse that appears on screen just after the title card and footage of atomic blasts is from Psalm 103:16 from the Bible (King James Version): "The deadly wind passeth over it / And it is gone; / And the place thereof / Shall know it no more..." Note the insertion of the word "deadly" which does not appear in the Bible.
In the 1994 book _Attack of the Monster Movie Makers_ by Tom Weaver, Phipps asserts in an interview that Oboler had already cast Leo Penn, future father of Sean Penn, as the lead and was looking to fill the role of Eric, the climber, when he asked Charles Laughton, "Who's your best person?" Laughton recommended Phipps, who was playing Petya, the perpetual student, in a stage production of Chekhov's "The Cherry Orchard" that he was directing, so Phipps had the scraggly beard. All ready to test for Eric, Phipps was surprised when Oboler said he wanted him to test for Michael, adding "nothing's set in concrete." The director liked Phipps for the lead, so he paid off Leo Penn.
In the early scenes when Roseanne is wandering alone, a sign says "Oak Ridge" and a store is identified as "Newton's." These are likely Oboler's sly references to Oak Ridge National Laboratory, the U.S. Department of Energy complex in Tennessee where weapons-grade plutonium was made for nuclear bombs during World War II, and Isaac Newton.
Charles' soliloquy is taken from the poem "The Creation" by noted African-American professor and diplomat James Weldon Johnson (1871-1938). It is part of his work "God's Trombones" published in 1927.