Veteran guide Gary Mechanic will lead a tour of the Chicago Portage National Historic Site on Saturday, Aug. 6 from 10 a.m. to noon at the site, which is located at 4800 S. Harlem Ave., just two blocks north of the Stevenson Expressway.

Mechanic will talk about the birth of Chicago, from the geological origins of the portage to how it is still functioning today. Tours require hiking about a half mile on a gravel path through the forest preserve area.

Wear long pants and walking shoes or boots. The event will take place rain or shine. Meet at the Joliet and Marquette monument near the park entrance. For more information visit www.chicagoportage.org.