I just added two ancient fortresses at Gubeikou in my GW map version 2 recently, here is simple introduction for them :
As the picture below , Red lane is main GW , two fortresses arounding walls indicating with white lanes and ping lane were built on different period ,the small fortress was built on Jing Dynasty (1115 - 1234) and large fortress(below the small one ) was built on Ming Dynasty(1368 - 1644). Red and white lane were built on Beiqi Dynasty (550 - 577),and pink lane was built on Ming Dynasty. In addtion to western wall beside river was ruinned , all walls are still existing now .
Ming's ruler expanded small fortress to be big one , and digged a pass through hill as the channel between two fortresses .
channel pictures as below are past and current looks respectively .
Attached kmz about Gubeikou in here is not available, please download my map version 2 in
map forum.
