the ruins of the ancient fort

age ancient asia barrier beijing blue brick cave china chuan colossal culture curve desert dynasty eastern famous fort fortification fortress frontier gray great gully hide hiding history invader ladder landmark landscape marvel ming mongolia mountain movie mud neolithic ning ningxia old ordos oriental path peking postcard prefecture protection qin rampart red ridge river ruin ruins scape scene scenic sky soldier steps stone studio tourist travel view wall war water west winter wonder world xia yellow yin yinchuan zhenbei