Between 1945 and 1962, the United States conducted over 200 nuclear tests up high in the atmosphere to learn about the power of nuclear weapons. The terrifying explosions were filmed from every possible angle and distance, and the movies — an estimated 10,000 of them — were then stored in high-security vaults scattered across the country.

Now, for the first time, about 4,200 of thee films have been scanned, and around 750 have been declassified by the US government. You can watch about 60 of them on YouTube. Some are in color, some in black and white, and all of them bear the whimsical names of top secret missions: Operation Hardtack, Operation Plumbbob, Operation Teapot.

The project is spearheaded by Lawrence Livermore National Laboratory (LLNL) weapon physicist Greg Spriggs, who’s hoping to save the films, reanalyze them, and squeeze every bit of data out of them. In fact, there’s still a lot we don’t know about the effects of high-altitude nuclear blasts, and right now they are prohibited by the Comprehensive Nuclear Test-Ban Treaty. By making the movies public and analyzing them, Spriggs hopes to help other nuclear weapon physicists learn more about nuclear explosions.

"We don't have any experimental data for modern weapons in the atmosphere,” Spriggs says in a video about the project. “The only data we have are the old tests, so it gets a little bit more complicated.”

Spriggs has so far reanalyzed about 400 to 500 films over the past five years. It’s key to digitize them because they’re made of old cellulose acetate, so they decompose over time. "You can smell vinegar when you open the cans,” he said in a statement. "We know that these films are on the brink of decomposing to the point where they'll become useless.”

Declassifying the films is a “huge bureaucratic undertaking,” writes Sarah Zhang in Wired. For each film, Spriggs has to fill out a form that then goes over to the Department of Energy for approval. The nuclear test operations are already known, so there’s no reason to keep the films secret, Spriggs tells Wired. It just takes a ton of time to declassify them. Thanks to Spriggs, and his time, we can now enjoy these explosive videos.