Beijin Great Wall - Beijing was not olny political center, but also being the important military affairs center in ancient china. if someone crossing the Yanshan mountain on the northward of beijing, they were able to enter the expansive plain of the northeast and control Mongolia llano, up to west of china.

therefore, the skillful craftsman constructed Peking Great Wall in every dynasties. there are 629kms of Beijing Great wall existed,in china today. 827 watch tower and 71pass were best preserved.