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 these 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.

Read more at TheVerge.com