Free admission to the Art Institute of Chicago is available to current Illinois educators, including pre-K–12 teachers, teaching artists working in schools, and homeschool parents. Educators can register online to receive a voucher for a complimentary ticket to the museum. This voucher must be presented—as a printed document or on a smart phone—with a valid educator ID at one of the museum’s admission counters. Learn more on our website at "Illinois Educator Admission Request."
Admission is free if you are an Illinois teacher; discount if you are a teacher. You will need a school I.D.
I hope this helps. It seems like you need to pre-register but should work if you're from Illinois. https://www.artic.edu/educators/visit-on-my-own/educator-admission-request
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