Families and adults alike will explore and learn about nature while having fun with Heller Naturalists in the outdoors. FEE IS PER PERSON. Children must be accompanied by a registered adult. Children two and under are free; please notify us at 847.433.6901 if you are bringing a young child not included in your registration. Highland Park Hikers #32016-18 is located under Nature Family Adventure Programs. Just click on 'Special Events With a Fee' in the left-hand column and then choose 'Heller Nature Center' below it!