• What to do: Nearly 17,000 years ago, a roving band of early North Americans set up camp at a rock overhang near what is now Avella. The site was used for centuries. Today, the Meadowcroft Rockshelter is one of the oldest recognized sites of human habitation on the continent, giving archeologists a rare glimpse into the lives of prehistoric people. The National Historic Landmark recently opened upgrades to the enclosure and museum.

• Contact: 724-587-3412, www.pghhistory.org/meadowcroft.