The Jungle...

The weather is still very hot. Over the weekend, however, temps were somewhat more bearable, meaning, it was about 84F-29C in the shade, so I decided to use it and go for a hike. It was quite interesting- part of the trail led through the jungle-like woods, and I also passed some very mysterious stone structures. My guess is they were used in the past to store water but I might be- and probably am- wrong. There was no one to ask. They were at the beginning of the trail, close to the road and nearby, now defunct mill. Any ideas?