A Wikipedia article about the walls and gates of the old city of Fongshan provides background information about the location of this geocache.
As I walked the length of the wall, I noticed that the construction of the wall as an elevated 2-meter-wide flat surface enhanced its usefullness as a defense. Defenders on the wall could easily observe others elsewhere on the wall or on the ground below, both close by and at a distance. But those on the ground close by could not so easily see those on the wall. On the east side, the brickwork protected defenders from the enemy while allowing the defenders to fire at their attackers or to move along the wall.
I noticed that there is a dry moat, a stream bed, outslde the wall on the east side. At close range, the moat would have provided a distracting hindrance for attackers, making them easier targets for the defenders. I saw that the small gaps in the wall allowed water to flow out through the wall at the same time that it prevented attackers from entering.
Finding the cache requires stealth. This area gets crowded, especially on weekends. The recent renovation of the site has increased the number of visitors. People walk to, around, and on the wall and gate. The geocache is located at a section of the wall that is visited a lot. Muggles may approach from below and behind you. The cache is tiny. It holds only a log. Please bring your own pen.
Along one side the wall is an unprotected drop-off without a railing.
The nearest public restroom facilities are those located 600 m away, 100 m southeast of the Dragon and Tiger pagodas. There is no source of water at the site. There are restaurants nearby. Busses 38B and 38C run along Chengfeng Road.