The entire section of Huangyaguan Great Wall is built on an abrupt yellow cliff, so it was so named. It is located 28km north of Ji County, Tianjin. Originally built in Tianbao 7th of Beiqi (557 AD), Huangyanguan was repaired for the first time in Ming Dynasty with bricks and for the second time in 1985. When appointed as the chief commanding officer in the Ji Garrison (one of the eleven garrisons of the Ming Dynasty), Qi Jiguang added watch towers and other defensive works. Watch towers, frontier cities, drain holes, emplacements, barracks and other indispensable military facilities are arranged orderly along the wall. With various forms of water towers presented along the walls, and the largest tower of the Great Wall 'Phoenix Tower' and the most unique 'Baguaguan Labyrinth', Huangyaguan is considered to be a miniature of the Great Wall.