The Thunderbird Paleoindian Site is not open to the public. But for a few years in the late 1970s, there was a museum to explore. Archaeologists were working at the site and made headlines when they found artifacts dating back 10,000 years. This was the oldest human settlement found in the mid-Atlantic states at that time.
Since then older artifacts have been found in other places, notably at Meadowcroft in Pennsylvania.
I was anxious to see Thunderbird so we took the kids there, which was south of Front Royal. The pictures I took then have faded and turned yellow, as did the pages of our "magnetic" photo album. (This was long before I learned about archival materials.)
In 1977 the site was named a National Historic Landmark. However, it is in private hands and cannot be accessed by public roads. A hint of the location remains in a road named Thunderbird in Limeton.
I believe the site borders on present-day Shenandoah River State Park, which did not exist at that time.
There is a short book about the site, "Lost Arrowheads and Broken Pottery but it is out of print.