In the center of the main park downtown there is a small memorial which features eight plaques dedicated to the men of Marion County who lost their lives in WWI & WWII. The sheer number of names was quite shocking to me, personally. There are literally hundreds.
The memorial lighthouse sits atop a bluff, visible from all over town and much of the river. Since Lighthouses weren't particularly common on the inland rivers, this is not historic. Enjoy the view of it atop the bluff, and save the hike. If you have young kids who need to run off some energy, this is the way to do it.