The oldest structures in Cairo date back only to the last couple of centuries BC during Greco-Roman period; however, on the fringes of the city stand the Giza Pyramids, some of the oldest structures on Earth. Despite their proximity to Cairo, the difference in age between the pyramids and the city itself are proof of their different histories. The pyramids at Giza and elsewhere in the desert near Cairo are a part of the legacy of an older city and civilization that fell into decline long before Cairo was founded. This civilization named this area Memphis, which was the seat of power to the Old Kingdom (2686—2181 BC) of Ancient Egypt, home to the pharaohs that raised the pyramids.