The Pyramids of Giza stand as humanity's most ambitious architectural achievements, three monumental pyramid tombs constructed during Egypt's Old Kingdom (2589-2500 BCE) on a limestone plateau 13 kilometers southwest of Cairo. The Great Pyramid of Khufu, the largest, originally stood 146.5 meters tall and was constructed from approximately 2.3 million limestone blocks, each precisely cut and fitted. Built as elaborate pharaonic tombs and spiritual monuments enabling the pharaoh's ascent to the afterlife, the pyramids demonstrate extraordinary engineering knowledge and organizational prowess. Designated a UNESCO World Heritage Site in 1979, the Pyramids of Giza attract approximately 4 million visitors annually and remain the only intact Wonder of the Ancient World.