It is just a fancy spire. Set alongside a rather busy road.
It was originally part of a design by Frank Lloyd Wright meant to sit atop a new capitol building, which was never built because of cost. The spire was still created and erected in Phoenix.
It is pretty, sure. And fairly close to Taliesin, where we found out about the spire while on the tour.
We actually accidentally drove by the spire on another day, following our GPS back to our hotel. We didn't think it warranted an actual out-of-the-car visit. We saw it from the car with an "Oh hey...is that...the Frank Lloyd Wright spire....?" and looked on our map to verify it.