Introduction to the Jiuyan Tower: The Nine Eyes Tower is named after the nine arrow windows on each side of the watchtower. It is also called the Wangjing Tower because the mountain is so high that one can see the city of Beijing on a clear day. This is one of the important passes of the Great Wall, with an altitude of 1141 meters. It is also one of the most famous scenic spots on the Great Wall. There are remains of stoves and living rooms in the building, and nearby are the remains of a horse farm, a horse drying ground, and a military camp (camp city).