When Ahmose I drove out the Hyksos rulers of Lower Egypt at the end of the Second Intermediate Period and reunited the country under his kingship he inaugurated the era that we now call the New Kingdom.
This is the period that shows up most often in documentaries about Ancient Egypt – it is the time of Tutankhamun, the time of Hatshepsut, the time of Ramesses II. It is the time of the great royal tombs in the Valley of the Kings, of the temples at Deir el Bahri, Medinet Habu, the Ramesseum, and on and on. In part this is because it was a high point of Egyptian history – Egyptian controlled territory reached its largest extent and the state was very wealthy and a player on the international stage. And in part it is because of what has survived – the discovery of Tutankhamun’s almost undisturbed tomb being one rather spectacular example!
The New Kingdom can be divided into two parts, punctuated by the Amarna Period. This is a period lasting only for the reign of Akhenaten, during which he moved the capital to Amarna (ancient Akhetaten) and attempted to reform the Egyptian religion. This replacement of the panoply of Egyptian gods by the worship of a single deity (the Aten) only via his intermediary (Akhenaten) didn’t much outlast Akhenaten himself, and neither did his new capital.
The decline of the New Kingdom began after the reign of Ramesses III – he had successfully fought off the Sea Peoples and while several other Bronze Age civilisations collapsed in this period (around 1150 BCE) Egypt wobbled but didn’t quite topple. It was the beginning of the end, however, and the power of the Pharaohs gradually declined while the power of the High Priests of Amun rose and the country become split practically into two parts by the end of the reign of Ramesses XI. This is the beginning of the Third Intermediate Period.