Years of covert Cold War-era nuclear weapons testing is now free to watch online.
The Defense Department has now declassified roughly 750 high-speed films. Dozens are posted on a national security lab's YouTube page.
For decades, these films were gathering dust and decaying. Researchers have been hurrying to convert them to digital before they decompose further.
These clips are just a small portion of the more than 10,000 taken of atmospheric bomb testing from 1945-1962.
Besides preservation, the footage has been converted to digital for more in-depth analysis.
Back when these tests were done, researchers were calculating by hand. Computer analysis has now shown a lot of the original data was wrong. Some answers were off by 20-30 percent.
The weapon physicist who's led the conversion effort says accuracy is important to keep the U.S. from using its nuclear arsenal.
He said, "If we ... show what the force of these weapons are and how much devastation they can wreak, then maybe people will be reluctant to use them."