Just an hour and a half west of Chicago, Starved Rock State Park attracts around 2 million visitors each year to view the sandstone-walled canyons on the south bank of the Illinois River. This geology is highly unusual for the Central Plains, and many of the park’s trails lead to waterfalls that are lush and green in summer. Those who’ve had their fill of nature can visit historic mansions and museums in nearby towns like Ottawa and Lasalle.