AUGUSTA — This Father’s Day, Mainers can visit state parks and historic sites for free as part of the Bureau of State Parks and Lands’ annual Maine Day. Father’s Day is June 20.

One event this year is the firing up of a 150-year-old oven at the Fort Knox State Historic site in Prospect that will cook up some baked goods. The oven was used to feed soldiers garrisoned at the fort.

This year marks the 75th anniversary of the Maine state parks system.