If you've never been to this remarkable historic site and history center just an hour west of Pittsburgh, — and plenty of Pittsburghers haven't — this offer of free entry is the perfect excuse.

Meadowcroft, in Avella, Washington County, is home to what's touted as the longest continuous site of human habitation in North America: a massive rock overhang used as a seasonal shelter by Native Americans as long as 16,000 years ago.

In addition to interpretive exhibits about that attraction, Meadowcroft (part of the John Heinz History Center), also includes a replica of a 16th-century Eastern Woodland Indian Village and two 1770s-era structures like those European settlers would have inhabited in the Upper Ohio Valley.

Visitors can use an atlatl — a spear-throwing implement used by prehistoric hunters — watch a blacksmithing demonstration, and more.

Courtesy of the Jack Buncher Foundation, admission to Meadowcroft is free this Saturday and Sunday for all adults, children and seniors. 

Meadowcroft is open noon-5 p.m. on Saturday and 1-5 p.m. on Sunday.

For more information, see here.