34 kilometers north of Lulong County seat , and at the northwest coruer of Qinhuangdao , Lioujiakou is the last pass along the Great Wall within Qinhuangdao area . It was first set up during the early years of Hongwu in Ming Dynasty .  

The mountains on both sides of the pass slope gently . With a river flowing through , the pass has a brick watchtower across the water constructed at the entrance . It is 10 meters long , 9 meters wide and 12 meters high , with an accommodation capacity for a hundred soldiers . The lower part of the tower is a 6.36-meter high water passage opening to the south . Above the opening hangs a stone board inscribed with the words " Liujiakou Pass " . The north and south walls of the tower have six arrow windows respectively while the east and west walls each has an opening and a window with the opening leading to the top of the Great Wall on either side . But it is no longer there now . At the upper part of the tower , there are spacious rooms that used to accommodate soldiers . On the wall in the middle of the tower inlays a tablet recording the reconstruction of the tower in the sixth year of Wanli ( 1578 ) . Now the tower at Liujiakou is the best preserved cross-water tower within Hebei Province .

In history , Liujiahou Pass once played an important role in the coronation of Zhu Di , or Emperor Yongle . In the first year of Jianwen ( 1399 ) when Zhu Di was still Prince of Yan stationed in Beiping ( now Beijing ) , one day , he discussed a punitive expedition against Zhu Quan , Prince of Ning , with his generals . One of them remarked , " To attack Prince of Ning , we must go through Songtingkou Pass ( now called Xifengkou Pass ) that is difficult to access . I am afraid we can’t make it . " Zhu Di then suggested , " How about taking a shortcut through Liujlakou Pass ? Then it won’t take much time to reach Daning ( now Ningcheng in Inner Mongolia ) . " So it was decided that they would start from Liujiakou and go northwards by the night . In October , Zhu Di took Daning as planned . He captured Prince of Ning alive and incorporated armies of Daning and Sanwei of Duoyan into his own forces . Later he went southwards and took Songtingkou Pass easily . Four years later , Prince of Yan dethroned Emperor Jianwen and proclaimed himself the emperor . It is just as the poem says , " Even forts of gold can not guard against enemies within , though pollen and butterfly were once in alliance with each other . "