Boris Bondarev urged a strong response from the West to Putin's threats, he told Sky News. Putin is using the nuclear button to "compel other countries to do whatever he wants," he said. If a fireball were to hit the city's Mission District, the Golden Gate Bridge would remain standing. In the event of a 15-kiloton blast, 63,000 people in San Francisco could die — but that's the smallest number of any city on this list. That blast would also miss two of the city's iconic waterside landmarks: the Ferry Building and Fisherman's Wharf. Golden Gate Bridge would remain standing....