A couple of short films from high altitude tests by the US Gov’t can be found here. The second film has the best shots of the explosions, and it’s also got this “happy bland” jazz music playing in the background for some strange reason.
That music is way too happy for nuclear explosions.
We’ll meet again,
Don’t know where,
don’t know whennn…
Check out this archive.org search…lots of big explosions 'n stuff 