Guangzhou's Yuexiu District has a dense and vibrant network of alleyways in nearly all areas, allowing large parts of the city to be criss-crossed without encountering motor vehicles.
This heavily-used bicycle and pedestrian alleyway used to be just a blank wall facing some nondescript shopfronts. The shopfronts on the south side have in recent years closed down (possibly they ran afoul of newly enforced restrictions on military operation of businesses) and the blank wall has been upgraded with some decorative inscriptions. The newly installed inscriptions on the wall face should make it easy enough to search without attracting undue attention.
Update in March 2022: the wall along the south with the closed row of temporary shopfronts has been demolished and is barricaded off pending completion of some construction. The cache is still in place.