A special event this week offers the chance to experience history at three historical park units in Southern Arizona — for free.

On Saturday, April 9, from 9:30 a.m. to noon, hikers can walk the 4-mile stretch of the Juan Bautista de Anza National Historic Trail between Tubac Presidio State Historic Park, in Tubac, and Tumacácori National Historical Park, in Tumacacori, before catching a free return shuttle back to Tubac. Additionally, admission to both parks will be free until noon that day.

All participants will receive their choice of a hiking-stick medallion or a pin representing each of the three park units — Tubac Presidio, Tumacácori and the trail. Children who participate can participate in an activity to become an Anza Trail "Junior Ranger," Tubac Presidio said in a news release. Additionally, everyone will receive an annotated map of the entire Anza Trail, which stretches from Culiacán, Mexico, to San Francisco.

The segment of the Anza Trail between the two parks is mostly level and shady, but participants should wear good walking shoes, dress for the weather and carry water and snacks, park officials said.

And when you're done with your excursion, there's plenty to do in the Tubac area. For starters, why not head over to Stables Ranch Grille for lunch?