Answer: the Soviets in October 1961 demonstrated the power of the hydrogen bomb when they detonate it.
Explanation: The hydrogen bomb is more deadlier than the atomic bomb American detonated in Japan, it can wipe an entire city killing tens of thousands.
The Soviets did demonstrated it power of the "staging" concept in October 1961, when they detonated the massive and unwieldy Tsar Bomba, a 50 megaton hydrogen bomb which derived almost 97% of its energy from fusion. This was the largest nuclear weapon developed and tested by any country in the world then.
