This article was originally published with the title “ A Stone Age Campsite at the Gateway to America ” in Scientific American Magazine Vol. 218 No. 6 (June 1968), p. 24 doi:10.1038 ...

Rock Island is located off the ... 1910 to 1964 by a wealthy inventor who built the stone buildings that dot the landscape. Typically, the campground remains open until the second Monday in ...