What Is This Structure In Youngsville?

I have seen this structure for years, right off of Chemin Agreeable in Youngsville, and I never knew its purpose.

I still don't know.  It resembles an observatory, but is it?

It's located near the intersection of Highway 339 and Chemin Agreeable on the south side of Youngsville, right next to what was once Just Judy's.

If you know what it is, chime in and let us know.