Mentioned by The Crazy Tourist
50 Best Things to Do in Chicago (IL
"In 37 acres and dating back to 1868, this zoo deserves extra credit as one of the last remaining free admission animal parks in the United States. There are more than 1,100 animals here, in habitats that are constantly being revamped. The polar bear and African penguin enclosures for instance have just been reopened, while a recent arrival in 2014 is the Regenstein Macaque Forest where you can see Japanese macaques bathing in a hot spring as they do in the wild."