It created a fireball 5 miles in diameter, destroyed all buildings up to 34 miles away, and could give 3rd degree burns to people 62 miles away. I can't even comprehend how one bomb could do so much damage.
Keep in mind that they dumbed it down quite a bit! It was 100 Megatons initially but they reduced it to only 50 Megatons "to reduce nuclear fallout (and also to prevent the blast from destroying the drop aircraft)".
Here's a segment from a Discovery channel documentary on the Tsar Bomba[1]. It is pretty difficult to visualise the kind of impact this bomb would have if actually dropped on a city. It would obliterate London (and large parts of England), as well as Paris, Madrid, Athens, Berlin, Vienna and countless other cities around the world if dropped.
I also read somewhere (but can't find the link) that although the Soviet pilots had special shutters and goggles to keep the flash out, when the bomb exploded they claimed they could see their bones through their hands.
Of course, the damage from this bomb (in terms of fallout) was much less than that resulting from the Castle Bravo test[2].
I read this headline with the narrator's voice from "Dr. Strangelove" (who had a similar line).
"Each B-52 can deliver a nuclear bombload of 50 megatons, equal to 16 times the total explosive force of all the bombs and shells used by all the armies in World War Two."
Well, that's the most powerful ever detonated, not necessarily the most powerful ever designed or built. Also I assume the current best is classified. We've probably surpassed that by a margin, given that FIFTY years have passed. The time between the first nuke and Tsar Bomba was 15 years. Now we have better science, more money, computers, and a 50 year lead.
However, as the "analysis" section of the wikipedia article mentions, ever since the invention of ICBMs and other more accurate and faster methods of delivering nuclear bombs, the trend has been towards carpeting the target area with smaller and more numerous bombs. Since the energy of the explosion is inversely proportional to the square of the distance, for destroying a specific area I suspect having multiple smaller explosions would be more effective than one large explosion.
