Atomic Blasts- Operations Greenhouse Through Upshot-Knothole - 1951-1953 - 29:22 - Color - Silent - This video shows a compilation of early atomic blasts taken from individual short films of the tests. These formerly classified films have never before been seen by the public. The video shows close up footage of boiling, tumbling, rolling fireballs of great destructive force as the nuclear power from the splitting of nuclei of atoms is unleashed. The blinding fury released by these early atomic devices demonstrates the show of power that was used by the United States to end World War II and establish a power base for the Cold War to follow.

The term "atomic" designated them as fission devices, as opposed to the later much more powerful thermonuclear devices, which used a fission test to start a fusion process. Eventually, the word "atomic" was replaced by the term "nuclear."

https://www.youtube.com/watch?v=8Pu_ZUl9YDM