Image of Allerton Manor by Jeremy Wilburn
The home isn't open to the public as it's used as a conference center, but the grounds are open (and free) to the public, and the park is a lovely place to wander. There is statuary all around the grounds.
A walled garden
But the reason I was thinking of Allerton Park today is because it's peony season, and there are almost 70 types of peonies there in the peony garden. Here's a link to a list of the varieties.
Illini Warrior peony image by Stephen Butler
Pillow Dreams peony image by Mark Lindner
So, if you're ever in central Illinois, pay a visit to Allerton Park. I think you'll enjoy it.