Operation Ivy was one of the many projects run by the US military during the Cold War to test atomic and thermonuclear weapons.
The Mike Shot was on October 31, 1952. (The referenced post contains an interesting video.) The Mike Shot was the first hydrogen bomb. The King Shot device was designed as a backup in case the Mike Shot failed.
The King shot seems to be of less interest to history. It was on 15 November 1952 at 23:30 GMT, that puts it at 19:30 EDT. (That’s 7:30 PM for anyone having trouble telling time.) King was the largest fission bomb we tested. “King” for “K” denoted kiloton. Where Mike was a 10 megaton fusion bomb (“M” for megaton), King was a 500 kiloton fission bomb. It was still quite large. The Gadget at Trinity and the Fat Man bomb, which was dropped on Nagasaki August 9th, 1945, were in the 20 kiloton range, while the Little Boy bomb dropped on Hiroshima, August 6th, 1945 was in the 16 kiloton range.
I know the news-real/propaganda films of the day are hard to take, with the “swelling music” and all. Still, it seems to me that we need to remember this history, or we could find ourselves repeating it in some way. The Cold War lasted a long time, and it never got hot in part because the people involved knew how bad these things were. Not “oh that’s bad” but knew exactly what these bombs could do.
Now we have rogue nations building bombs, and no one seems to understand how bad that is. How horrible these things really are. (And no, I hold little confidence that the people currently in Washington – of any party – have a clew.)