Admission to the park is free from 9 a.m. to 5 p.m., Saturday, Sept. 28, as part of an annual event hosted by Smithsonian Magazine. Attractions include artifacts, displays, a demonstration of an 1859 printing press, and living history presentations about the daily lives of Spanish soldiers and civilians who lived in Tubac from 1752 through 1776. For admission, print free tickets from smithsonianmag.com/museumday.