Of course, the reason for looking for something like that is so I can go investigate. I went out there the first time on a day that it was too hot to do any climbing. It was almost too hot to walk around on mostly level ground. The temperature was only about 102 when I started out, and it was close to sunset, but I had to drink a lot of water. I misread my GPS receiver and thought I was only half a mile from the center of the circles when I started out. Actually, I was almost 2 miles away. It was close to sunset when I realized my mistake. I was only 0.2 mile from the center then but I figured it could be difficult to find the truck in that flat, featureless area in the dark so I turned back.
I went back about a week later. I went a little earlier and it was cooler and I had a plan for getting closer to the circles before I got out of the truck. It's monsoon season, though. There were some large clouds growing east of my destination. I kept going even though I might not get to the circles again. It would be cool to be in a rainstorm.
After a while it looked like it was going to rain where I was and since getting there involved driving several miles on dirt roads and because I didn't want to be stuck in mud out there, I turned around when I was about 0.2 mile from the center, again. I could see rain falling on the Superstition Mountains on the way back and stopped with a view of those mountains as the sun set.
I was there for about 30 minutes getting pictures of the storm and the sunset in the other direction.
The very next day I made my third attempt to get to the circles. As I walked toward the center of the circles, I imagined that maybe it was some sort of ancient American Indian site, used for astronomy and to predict when crops should be sown or harvested and other such things. The American equivalent of Stonehenge. I would be famous for discovering it.
At 0.1 mile from the center, I saw a couple of pieces of metal and wondered what some cowboys had disposed of out there. I took a few steps and saw some more. Then more and more and more. There were pieces of metal all over the place. Many of the pieces were repeated. Lots of 3 inch pieces of pipe with a nut on one end. Lots of U shaped rods. Lots of sheet metal that looked like it had been formed into a cylinder and then smashed into the ground at high speed. Hmm.
Well, you get the idea. Anyway, after looking at dozens of pieces and remembering that that area is sometimes used by the National Guard for practice, I realized that the circles were a target and all the metal was pieces of practice bombs. For several reasons that I won't get into here, I concluded that the practice bombs didn't contain explosives. Then I proceeded to touch or move nothing, just in case my conclusion was wrong. I walked around gingerly for a little while looking for the circles but couldn't see them from the ground. It was a while before I noticed something a little unusual about the target area.
Give up? There are no saguaros. They are everywhere else out there, but I could only find one within the target area. I wonder if they were removed before the target was put there or if they were wiped out by target practice. The other plants there could survive damage or re-populate the area in a few decades. It could be a couple of hundred years before there are many saguaros there, though.
There are lots of pictures if you want to look at them all.