Sebastien Roblin
When the Tu-16 was designed in the 1950s, the intent was for strategic bombers to overfly hostile cities and military installations, and rain gravity bombs—conventional or nuclear—on top of them. The World War II–era roots of the concept were even reflected in the H-6’s defensive armament of six twenty-three-millimeter automatic cannons stationed in the belly, tail and top turret, and a seventh in the aircraft’s “glazed” (glass) nose, intended to shoot up hostile fighters.
http://nationalinterest.org/blog/the-buzz/fact-you-may-not-know-china-has-its-very-own-b-52-bomber-22856