Bravo! Excellent episode! One can only imagine the hard labor put into building the amazing great walls! You can also tell that the First Trick has been eroding and perhaps someday, into the great future, it will be gone……impermanence. Thank you so much for sharing!
Page 9:16 notice the cascaded door? When closed those door formed double layer protection. This is unique to China and not found in other countries. 第 9:16 页 注意到层叠门了吗?当关闭时,这些门形成双层保护。这是中国独有的,其他国家没有的。