A state park north of my hometown (Peoria, IL) is probably the first place I ever went on a hike. It’s called Starved Rock, so named because of a scrum between two warring Indian tribes that ended with one tribe laying siege to members of the other on this rock overlooking the Illinois River. As I recall, the besiged tribespeople starved themselves to death rather than surrender.
The park has lots of cliffs and canyons; you don’t imagine errant hikers plummeting from high cliffs to an untimely demise on the plains of Illinois, but it happens. Here’s a story from my old newspaper reminding hikers (and re-reminding them a few more times in case they didn’t catch the previous reminders — apparently the paper had extra space to fill) to Stay on the Trails and Stay Alive.
This park and another one in the northwest corner of Illinois called Mississippi Palisades State Park have some of the best scenic vistas in the state. Very good by flatlands standards, in any case.