Mystery Landmarks in Texarkana

I have lived in Texarkana my entire life, and I have seen a couple of "mystery landmarks," as I call them, that have me wondering what on earth they are. Maybe you can help me determine what they are.

The first mystery landmark is something I see a lot. It's in a field right by the Rotary Splash Pad in Spring Lake Park. This circle is pretty big. It's more than 50 feet wide and the path is about 6 feet wide. Is it some sort of track? Maybe some old area for horses?

Spring Lake Park was once the home of the "Four States Fair" when I was a kid so perhaps it has something to do with that. Do you know?

The next mystery landmark is out in the middle of a field just off of Summerhill Road. It is the tall white object in the distance in the above photo. I have seen it so many times over the years. If I recall correctly, we even parked next to it as teenagers as we made the infamous "shuffle run" on the weekends.

But as for this landmark, this photo shows you as close as I could get to it. That's because when I got out of my Jeep to take the picture, a gentleman came out and told me if I got any closer to the fence I would be trespassing.

I have always wondered if it was some post Cold War item? Does it have a purpose? Is it some storm warning beacon? One thing's for sure, it's a mystery.