Nine Eyes Tower (Jiuyan Lou) (九眼楼自然风景区)

Jiuyan Watchtower is a double-story building with square section, whose name originated from the nine holes on each side of the wall. The remained one story is 7.8 meters tall 13 meters long containing a 1.2-meter-wide loop track for patrolling. And each hole is 1.65 meters tall and 0.5 meters wide.

The Jiuyan Watchtower is magnificent and firm, whose base is made up of slabs of stones and the upper part was built with grey bricks. A terrace on the west side of the tower is for gathering soldiers. On the north of the terrace, there are steps made up of bricks leading to the south gate. The roof is built with bricks in arched shape. There is a large space for accommodation and storing weapons inside the tower. There are two windows facing the north. And each side of the tower is fitted with a 2-meter-tall 1.2-meter-wide door for the sake of convenience.

The Jiuyan Watchtower has the largest scale and most holes among watchtowers along the Great Wall, and has a strategic significance in military defense. It is located in the intersection of three key towns of Xuan, Ji and Chang, and also connects the inner Great Wall and outer Great Wall. Such a key position is unparalleled among watchtowers of the Great Wall. You can find 24 inscriptions bearing poems, most of which are admiration of the beauty of the tower as well as the expression of authors' ambition. It is rare that so many poems carved in a watchtower. But it also shows status and uniqueness of the Jiuyan Watchtower.

The watchtower is surrounded by mountains, massive trees, gullies and clouds. In the southeast, Yanqi Lake reservoir sits in mountains. And downtown Beijing lies in the southwest.