I didn't see that the largest test by the USA (Castle Bravo 1954) mentioned anywhere. What is your point? Also, most of the documentation I have seen indicates that the HOB for the 57 megaton Soviet test was 12,000 feet.
I'm still looking, slim. I haven't found any pictures of anything bigger than 25 Mega-Ton (2500 KTon) yet. But, I am still looking and will post when and if I find one. Whatever the picture looks like, It must be absolutely AWESOME!
The 25 Megaton explosion is truly frightful. Can you imagine a 61 Megaton? YIKES!!!!
BELOW - ONE OF AMERICA'S LARGEST EXPLOSIONS!
Below is the Castle Bravo Detonation. This is a very very controversial test in several ways. The Castle Bravo was Detonated on Eniwetok Atoll in 1954. The result was a truly massive explosion, the biggest the DoE every managed, and it was all by accident!!!
The Bomb was only to have a predicted Yield of 6Mt, much smaller than Ivy Mike. The resulting chain reaction managed to cunjure up a whopping 15Mt Yield(15,000,000 tons of TNT equilivent)
(The largest is 61 MegaTon or 10 times larger than this one.)
This massive detonation blew half of the Atoll away. Although it made the biggest ever explosion in America's history(albeit by accident) it also produced the worlds first and very devastating Nuclear disaster. This was because the fact it was all done by accident. The Predicted 6MT explosion would of been 'within limits' but the whopping 15MT explosion that occurred caused extreme amounts of Nuclear fall-out and the whole area for hundreds of miles was completely contaminated. This mushroom cloud loomed over hundreds of miles and fell down on many Atolls and Islands with thousands of local inhabitants of Marshall Islander's and Japanese.
The result was many hundreds killed. Most of the Islanders got effected with 100-200R of fall-out and died of a horrible and painful death, some very slowly. Japanese fisherman were also caught in the fall-out well outside the exclusion zone like the islanders were. The japanese fisherman, although miles and miles outside the 'zone of danger' were contaminated with over 300R of fall-out and some of the crew died within a few days of exposure.
Many of the islander's children were born with serious deformalities that are reminiscent to todays Chernobyl nuclear disaster.
After this 'accidental' over-rated explosion, the DoE expanded its safe-zone to over 1% of the World's Surface around this Atoll incase other experiments went drastically wrong making it the largest military testing ground on earth.
![](http://www.dreamlandresort.com/richard/Cbravo1.jpg)
The Resulting absolutely massive Fireball rising up into a dome shape with a hollow middle. burning its way through the atmosphere. The Radiant heat was so much that it would of melted steel in seconds on the Atoll.
This however was not the largest ever Nuclear Detonation
As a side note...The Russians also did a large explosion, but this time it was predicted to be as large as it was. Well over 15MT this Giant was detonated on a large island. The resulting effect was the island 'disappeared'