The Giza Necropolis is the oldest of the ancient Wonders and the only one still in existence.A unified kingdom was founded c. 3150 BCE by King Menes, leading to a series of dynasties that ruled Egypt for the next three millennia. Egyptian culture flourished during this long period and remained distinctively Egyptian in its religion, arts, language and customs. The first two ruling dynasties of a unified Egypt set the stage for the Old Kingdom period, c. 2700–2200 BCE, which constructed many pyramids, most notably the Third Dynasty pyramid of Djoser and the Fourth Dynasty Giza pyramids.The First Intermediate Period ushered in a time of political upheaval for about 150 years.Stronger Nile floods and stabilisation of government, however, brought back renewed prosperity for the country in the Middle Kingdom c. 2040 BCE, reaching a peak during the reign of Pharaoh Amenemhat III. A second period of disunity heralded the arrival of the first foreign ruling dynasty in Egypt, that of the Semitic Hyksos.