Between 1945 and 1962, the United States Department of Energy conducted 210 atmospheric nuclear tests. Each test was captured by multiple cameras at around 2,400 frames per second—an estimated 10,000 films overall. For decades, most of those films collected dust and began to decompose in high-security vaults scattered across the country.

Until last March.

After spending several years hunting down the footage, weapon physicist Greg Spriggs and a team of physicists at Lawrence Livermore National Laboratory in California located about 6,500 of the films, and have since declassified about 750 of them.

According to the LLNL website, one of the goals of the project was to ensure that today’s post-testing era scientists who are using computer codes are working with the most accurate data. But Spriggs and his team got more than they bargained for when they took a closer look at the films. They discovered that much of the published data from the tests were incorrect—sometimes off by as much as 20 to 30 percent. That meant that all the films would need to be reanalyzed.

[The next big engineering tool of the 1960s? Nuclear bombs.]

“When you go to validate your computer codes, you want to use the best data possible,” he said on the LLNL website. “One of the payoffs of this project is that we’re now getting very consistent answers. We’ve also discovered new things about these detonations that have never been seen before. New correlations are now being used by the nuclear forensics community, for example.”

Another reason the project is so important to Spriggs?

“It’s just unbelievable how much energy’s released,” he said in a post on the LLNL’s website. “We hope that we would never have to use a nuclear weapon ever again. I think that if we capture the history of this and show what the force of these weapons are and how much devastation they can wreak, then maybe people will be reluctant to use them.”

See for yourself:

[Babysitting bombs is no easy feat.]

All videos are courtesy of Lawrence Livermore National Laboratory. You can view all 63 available videos in an online archive.