A short expanse of lawn, lying below and immediately adjacent to the north side WPA pergola is popularly known as the "grassy knoll," the name it was given in the Warren Commission and other reports dealing with the assassination of President John F. Kennedy.

On November 22, 1963 Dallas businessman Abraham Zapruder used a home movie camera to film the presidential motorcade. In the process, he chanced to capture a visual record of the assassination as it happened, while standing atop the concrete pedestal seen in this photo to the right.