Digging a new route to China? Building a sand castle? Re-creating an archaeological dig in Princeton? What were these young men and women doing? Archivists offer no information on this photo, although the presence of two women (and the hairstyles sported by the men) would indicate that it was taken in the early 1970s. A car in the background looks like a Chrysler  from the early 1960s. Can any readers enlighten us regarding what these folks were up to or who they are?