There is no cemetery in Illinois that has a wilder variety of history than Rosehill. It's the final resting place of many of Abraham Lincoln's friends. Oh, and it might also include a vampire.
There is a former riverboat casino that is abandoned and still floating on the Illinois/Iowa border nearly adrift in the Mississippi River near Burlington.
When you learn about the infamous Schweppe Mansion near Chicago, you'll likely be stuck in the weird place of wanting this beautiful home and being terrified of it.