As an ancient military place, Zhangbi Ancient Fort has a superior geographical location, backed by mountains, and can carry out tunnel warfare, which has the advantages of easy to guard and difficult to attack. The tunnel construction is particularly good, and there are many forks. If there is no sign, it will most likely get lost, but some places have not been opened, which is good. Huancuoliu can be described as the protector of Zhangbi Ancient Castle. It has a history of thousands of years and is worth watching.