The 7th annual Museum Day is set for Saturday.
A downloadable ticket on the magazine's website can be used for free admission for two visitors at participating museums.
Illinois museums and cultural venues from the Adler Planetarium in Chicago to the University Museum in Carbondale are taking part in the one-day event.
Last year, more than 220,000 tickets were downloaded nationwide for 1,300 venues in all 50 states, Washington and Puerto Rico.
Online: www.smithsonianmag.com/museumday
