> what exactly is so magical about the "strike" that they
> might be compelled to build a string of pyramids along it?
(Lehner, Complete Pyramids, 1997, 106-7)
The southeast corners of the pyramids of Khufu, Khafre and Menkaure are nearly aligned on the great Giza Diagonal that runs about 43° east of true north, almost perpendicular to the dip of the plateau. This follows what geologists call the strike of the Mokattam Formation, that is, a line perpendicular to the slope. When you walk along a hill without going up or down, you are following its strike. By aligning themselves to this, the builders ensured that the bases of the three main pyramids were at approximately the same level, although the base of Khafre’s is about 10m (33 ft) higher than Khufu’s.