China has recently completed major upgrades to
a complex of naval bases at Zhoushan and Dinghai (about 180 kilometers south of Shanghai). Over a dozen submarines
and over 30 destroyers and frigates can operate of this complex, most of them
in underground docks dug into seaside hills. There are also repair and
maintenance facilities, as well as underground fuel and ammunition depots.
Nearby air bases for naval aviation also feature some underground hangers, and
many above ground aircraft shelters.
This complex of bases
was built up since the 1990s, in anticipation of an invasion of Taiwan. While
China has backed off on the aggressive rhetoric of late, building continues at
these naval bases.