Mentioned by 10Best
10 free things to do in Chicago year-round
"An ape house, a birdhouse and a working model of a five-acre Midwestern farm are just a few examples of what makes this zoo special. Founded in 1868 and known as America's oldest free public zoo, the Lincoln Park Zoo still manages to charge no admission and remains open year-round. Set on scenic park grounds with lush lawns and pleasant walkways, the zoo greets visitors with the beauty of Georgian Revival buildings and a spectacular greenhouse."