On the site of Dahshur, 40km to the south of Cairo, are two breathtakingly beautiful pyramids. Two revolutionary monuments which would seem to be the first real pyramids, a link in the chain which is essential to understanding the evolution in the building of pyramids. To the south is the unusual rhomboidal Bent Pyramid. To the north is the Red Pyramid, which may well be the very first triangular pyramid to have been built.