In the original script for the 1985 movie Back to the Future, screenwriter Bob Gale wanted Marty McFly (Michael J. Fox) to travel back in time by driving into a nuclear test site in Nevada and using the power of a nuclear explosion during a bomb test.
The concept ended up being declined after Gale and director Robert Zemeckis realized that just that scene alone would cost over $1 million to shoot. The scene was really all storyboarded out, and it looks like it would have been great! But in the end, lightning hitting the clock tower is what we shoot for the movie. Gale told Collider:
“The idea that the DeLorean was nuclear powered, literally they needed to harness nuclear energy to send the time machine back to the future. Bob [Zemeckis] and I had seen The Atomic Café documentary, a movie called The Atomic Kid which we pay homage to on the marquee of the town theater in 1955 – one of the most perverse movies ever made… We were obsessed with the idea of ‘Hey wouldn’t it be cool if we could recreate one of these towns and blow it up?’ And you know, hey, okay yeah you’re a writer, you can write anything in the script that you want. So we wrote this elaborate sequence in and in the original version, the time machine was built into a refrigerator which was a time chamber. And that was where Marty was gonna be when the nuclear blast went off.”
When talking about cutting the scene, he said:
“When it came time to cut the budget – and this was before we cast Eric Stoltz – the studio said, ‘Hey you guys can make the movie, but cut $1 million out.’ Bob and I looked long and hard at the script and said, ‘What do we cut? How do we save $1 million?’ And the most expensive thing was going on location and building this town. And we said well, if we can cut that out – if we can cut going on location and building a town and do something on a location that we already have, namely the backlot, that would save us $1 million easy. Over a weekend we spent time walking around on the backlot going back and forth to our offices, and we came up with the whole clock tower sequence. Flash forward to Indiana Jones 4 and you’ll see that Steven Spielberg was inspired by the original ending to Back to the Future.”
You can watch how the scene would have played out in the video below featuring the original storyboards. This scene sees Marty drive the DeLorean right into an atomic blast.