Places I'd like to see in Columbus, Ohio

We just finished a short stay in Columbus, Ohio. On a future visit, I'd like to see:

• the Scioto Mile
• the Topiary Park, especially since Seurat's A Sunday Afternoon on the Island of La Grande Jatte is my favorite piece at the Art Institute
• actually seeing the roses at the Columbus Park of Roses (we didn't get beyond the playground before it started raining)

I'd also like to return to the Columbus Zoo, which was really well done - definitely up there among the zoos that I've visited. I want to spend more time in the Heart of Africa section.