Imagine the destruction that did but with the magnitude of 10 times that!
I'll just point out that the bombs dropped on Japan to end WW2 were around 15kT each. Modern thermonuclear weapons available to the longstanding nuclear powers go up to 25MT - more than 1500
times more powerful.
In the event of all out nuclear war, I'd hope to be very close-by when one goes off - I sure as hell wouldn't want to be one of the 'survivors' of a nuclear war.